diff --git a/debuggerd/proto/tombstone.proto b/debuggerd/proto/tombstone.proto
index 38a06f4..2c7156b 100644
--- a/debuggerd/proto/tombstone.proto
+++ b/debuggerd/proto/tombstone.proto
@@ -3,6 +3,9 @@
 option java_package = "com.android.server.os";
 option java_outer_classname = "TombstoneProtos";
 
+// NOTE TO OEMS:
+// If you add custom fields to this proto, do not use numbers in the reserved range.
+
 message Tombstone {
   Architecture arch = 1;
   string build_fingerprint = 2;
@@ -24,6 +27,8 @@
   repeated MemoryMapping memory_mappings = 17;
   repeated LogBuffer log_buffers = 18;
   repeated FD open_fds = 19;
+
+  reserved 20 to 999;
 }
 
 enum Architecture {
@@ -31,6 +36,8 @@
   ARM64 = 1;
   X86 = 2;
   X86_64 = 3;
+
+  reserved 4 to 999;
 }
 
 message Signal {
@@ -46,15 +53,21 @@
 
   bool has_fault_address = 8;
   uint64 fault_address = 9;
+
+  reserved 10 to 999;
 }
 
 message Cause {
   string human_readable = 1;
+
+  reserved 2 to 999;
 }
 
 message Register {
   string name = 1;
   uint64 u64 = 2;
+
+  reserved 3 to 999;
 }
 
 message Thread {
@@ -63,6 +76,8 @@
   repeated Register registers = 3;
   repeated BacktraceFrame current_backtrace = 4;
   repeated MemoryDump memory_dump = 5;
+
+  reserved 6 to 999;
 }
 
 message BacktraceFrame {
@@ -76,6 +91,8 @@
   string file_name = 6;
   uint64 file_map_offset = 7;
   string build_id = 8;
+
+  reserved 9 to 999;
 }
 
 message MemoryDump {
@@ -83,6 +100,8 @@
   string mapping_name = 2;
   uint64 begin_address = 3;
   bytes memory = 4;
+
+  reserved 5 to 999;
 }
 
 message MemoryMapping {
@@ -97,6 +116,8 @@
   string mapping_name = 7;
   string build_id = 8;
   uint64 load_bias = 9;
+
+  reserved 10 to 999;
 }
 
 message FD {
@@ -104,11 +125,15 @@
   string path = 2;
   string owner = 3;
   uint64 tag = 4;
+
+  reserved 5 to 999;
 }
 
 message LogBuffer {
   string name = 1;
   repeated LogMessage logs = 2;
+
+  reserved 3 to 999;
 }
 
 message LogMessage {
@@ -118,4 +143,6 @@
   uint32 priority = 4;
   string tag = 5;
   string message = 6;
+
+  reserved 7 to 999;
 }
diff --git a/fs_mgr/libfiemap/fiemap_writer.cpp b/fs_mgr/libfiemap/fiemap_writer.cpp
index 621031a..8acb885 100644
--- a/fs_mgr/libfiemap/fiemap_writer.cpp
+++ b/fs_mgr/libfiemap/fiemap_writer.cpp
@@ -52,7 +52,7 @@
 static constexpr const uint32_t kUnsupportedExtentFlags =
         FIEMAP_EXTENT_UNKNOWN | FIEMAP_EXTENT_UNWRITTEN | FIEMAP_EXTENT_DELALLOC |
         FIEMAP_EXTENT_NOT_ALIGNED | FIEMAP_EXTENT_DATA_INLINE | FIEMAP_EXTENT_DATA_TAIL |
-        FIEMAP_EXTENT_UNWRITTEN | FIEMAP_EXTENT_SHARED | FIEMAP_EXTENT_MERGED;
+        FIEMAP_EXTENT_UNWRITTEN | FIEMAP_EXTENT_SHARED;
 
 // Large file support must be enabled.
 static_assert(sizeof(off_t) == sizeof(uint64_t));
diff --git a/fs_mgr/libsnapshot/cow_reader.cpp b/fs_mgr/libsnapshot/cow_reader.cpp
index 75c05d1..cf9f6ea 100644
--- a/fs_mgr/libsnapshot/cow_reader.cpp
+++ b/fs_mgr/libsnapshot/cow_reader.cpp
@@ -237,6 +237,7 @@
                                [](CowOperation& op) { return IsMetadataOp(op); }),
                 ops_.get()->end());
 
+    set_total_data_ops(ops_->size());
     // We will re-arrange the vector in such a way that
     // kernel can batch merge. Ex:
     //
diff --git a/fs_mgr/libsnapshot/include/libsnapshot/cow_reader.h b/fs_mgr/libsnapshot/include/libsnapshot/cow_reader.h
index 62b54f9..1de7473 100644
--- a/fs_mgr/libsnapshot/include/libsnapshot/cow_reader.h
+++ b/fs_mgr/libsnapshot/include/libsnapshot/cow_reader.h
@@ -142,6 +142,10 @@
 
     void InitializeMerge();
 
+    void set_total_data_ops(uint64_t size) { total_data_ops_ = size; }
+
+    uint64_t total_data_ops() { return total_data_ops_; }
+
   private:
     bool ParseOps(std::optional<uint64_t> label);
 
@@ -152,6 +156,7 @@
     uint64_t fd_size_;
     std::optional<uint64_t> last_label_;
     std::shared_ptr<std::vector<CowOperation>> ops_;
+    uint64_t total_data_ops_;
 };
 
 }  // namespace snapshot
diff --git a/fs_mgr/libsnapshot/snapuserd.cpp b/fs_mgr/libsnapshot/snapuserd.cpp
index 0a02bd0..d620300 100644
--- a/fs_mgr/libsnapshot/snapuserd.cpp
+++ b/fs_mgr/libsnapshot/snapuserd.cpp
@@ -424,6 +424,7 @@
     }
 
     SNAP_LOG(DEBUG) << "Merge success: " << merged_ops_cur_iter << "chunk: " << chunk;
+    merge_initiated_ = true;
     return true;
 }
 
@@ -445,6 +446,19 @@
     return next_chunk;
 }
 
+void Snapuserd::CheckMergeCompletionStatus() {
+    CowHeader header;
+
+    if (merge_initiated_) {
+        reader_->GetHeader(&header);
+        SNAP_LOG(INFO) << "Merge-status: Total-Merged-ops: " << header.num_merge_ops
+                       << " Total-data-ops: " << reader_->total_data_ops();
+    } else {
+        SNAP_LOG(INFO) << "Merge was not initiated. Total-Merged-ops: " << header.num_merge_ops
+                       << " Total-data-ops: " << reader_->total_data_ops();
+    }
+}
+
 /*
  * Read the metadata from COW device and
  * construct the metadata as required by the kernel.
@@ -818,11 +832,13 @@
                    << " Num Sector: " << ChunkToSector(data_chunk_id)
                    << " Replace-ops: " << replace_ops << " Zero-ops: " << zero_ops
                    << " Copy-ops: " << copy_ops << " Areas: " << vec_.size()
-                   << " Num-ops-merged: " << header.num_merge_ops;
+                   << " Num-ops-merged: " << header.num_merge_ops
+                   << " Total-data-ops: " << reader_->total_data_ops();
 
     // Total number of sectors required for creating dm-user device
     num_sectors_ = ChunkToSector(data_chunk_id);
     metadata_read_done_ = true;
+    merge_initiated_ = false;
     return true;
 }
 
diff --git a/fs_mgr/libsnapshot/snapuserd.h b/fs_mgr/libsnapshot/snapuserd.h
index dba3186..518d08b 100644
--- a/fs_mgr/libsnapshot/snapuserd.h
+++ b/fs_mgr/libsnapshot/snapuserd.h
@@ -70,6 +70,7 @@
     const std::string& GetMiscName() { return misc_name_; }
     uint64_t GetNumSectors() { return num_sectors_; }
     bool IsAttached() const { return ctrl_fd_ >= 0; }
+    void CheckMergeCompletionStatus();
     void CloseFds() {
         ctrl_fd_ = {};
         cow_fd_ = {};
@@ -141,6 +142,7 @@
     std::map<sector_t, const CowOperation*> chunk_map_;
 
     bool metadata_read_done_ = false;
+    bool merge_initiated_ = false;
     BufferSink bufsink_;
 };
 
diff --git a/fs_mgr/libsnapshot/snapuserd_server.cpp b/fs_mgr/libsnapshot/snapuserd_server.cpp
index 68a00a0..017de3b 100644
--- a/fs_mgr/libsnapshot/snapuserd_server.cpp
+++ b/fs_mgr/libsnapshot/snapuserd_server.cpp
@@ -214,6 +214,7 @@
 
     auto misc_name = handler->misc_name();
     LOG(INFO) << "Handler thread about to exit: " << misc_name;
+    handler->snapuserd()->CheckMergeCompletionStatus();
 
     {
         std::lock_guard<std::mutex> lock(lock_);
diff --git a/libcutils/trace-dev.inc b/libcutils/trace-dev.inc
index 6543426..80205bc 100644
--- a/libcutils/trace-dev.inc
+++ b/libcutils/trace-dev.inc
@@ -21,6 +21,7 @@
 
 #include <errno.h>
 #include <fcntl.h>
+#include <fnmatch.h>
 #include <limits.h>
 #include <pthread.h>
 #include <stdatomic.h>
@@ -116,7 +117,7 @@
     for (int i = 0; i < count; i++) {
         snprintf(buf, sizeof(buf), "debug.atrace.app_%d", i);
         property_get(buf, value, "");
-        if (strcmp(value, "*") == 0 || strcmp(value, cmdline) == 0) {
+        if (fnmatch(value, cmdline, FNM_NOESCAPE) == 0) {
             return true;
         }
     }
diff --git a/libprocessgroup/include/processgroup/processgroup.h b/libprocessgroup/include/processgroup/processgroup.h
index 1cadc9f..1aaed7b 100644
--- a/libprocessgroup/include/processgroup/processgroup.h
+++ b/libprocessgroup/include/processgroup/processgroup.h
@@ -36,7 +36,8 @@
 
 static constexpr const char* CGROUPS_RC_PATH = "/dev/cgroup_info/cgroup.rc";
 // Path to test against for freezer support
-static constexpr const char* CGROUP_FREEZE_PATH = "/sys/fs/cgroup/freezer/cgroup.freeze";
+// TODO: remove and replace with a function call, see http://b/180056337
+static constexpr const char* CGROUP_FREEZE_PATH = "/sys/fs/cgroup/uid_0/cgroup.freeze";
 
 bool UsePerAppMemcg();
 
diff --git a/libprocessgroup/processgroup.cpp b/libprocessgroup/processgroup.cpp
index d669ebe..209ccd9 100644
--- a/libprocessgroup/processgroup.cpp
+++ b/libprocessgroup/processgroup.cpp
@@ -131,13 +131,25 @@
     return StringPrintf("%s/uid_%d/pid_%d", cgroup, uid, pid);
 }
 
-static int RemoveProcessGroup(const char* cgroup, uid_t uid, int pid) {
-    int ret;
-
+static int RemoveProcessGroup(const char* cgroup, uid_t uid, int pid, unsigned int retries) {
+    int ret = 0;
     auto uid_pid_path = ConvertUidPidToPath(cgroup, uid, pid);
-    ret = rmdir(uid_pid_path.c_str());
-
     auto uid_path = ConvertUidToPath(cgroup, uid);
+
+    if (retries == 0) {
+        retries = 1;
+    }
+
+    while (retries--) {
+        ret = rmdir(uid_pid_path.c_str());
+        if (!ret || errno != EBUSY) break;
+        std::this_thread::sleep_for(5ms);
+    }
+
+    // With the exception of boot or shutdown, system uid_ folders are always populated. Spinning
+    // here would needlessly delay most pid removals. Additionally, once empty a uid_ cgroup won't
+    // have processes hanging on it (we've already spun for all its pid_), so there's no need to
+    // spin anyway.
     rmdir(uid_path.c_str());
 
     return ret;
@@ -176,7 +188,7 @@
     std::vector<std::string> cgroups;
     std::string path;
 
-    if (CgroupGetControllerPath("cpuacct", &path)) {
+    if (CgroupGetControllerPath(CGROUPV2_CONTROLLER_NAME, &path)) {
         cgroups.push_back(path);
     }
     if (CgroupGetControllerPath("memory", &path)) {
@@ -212,19 +224,49 @@
     }
 }
 
+/**
+ * Process groups are primarily created by the Zygote, meaning that uid/pid groups are created by
+ * the user root. Ownership for the newly created cgroup and all of its files must thus be
+ * transferred for the user/group passed as uid/gid before system_server can properly access them.
+ */
 static bool MkdirAndChown(const std::string& path, mode_t mode, uid_t uid, gid_t gid) {
     if (mkdir(path.c_str(), mode) == -1 && errno != EEXIST) {
         return false;
     }
 
-    if (chown(path.c_str(), uid, gid) == -1) {
-        int saved_errno = errno;
-        rmdir(path.c_str());
-        errno = saved_errno;
-        return false;
+    auto dir = std::unique_ptr<DIR, decltype(&closedir)>(opendir(path.c_str()), closedir);
+
+    if (dir == NULL) {
+        PLOG(ERROR) << "opendir failed for " << path;
+        goto err;
+    }
+
+    struct dirent* dir_entry;
+    while ((dir_entry = readdir(dir.get()))) {
+        if (!strcmp("..", dir_entry->d_name)) {
+            continue;
+        }
+
+        std::string file_path = path + "/" + dir_entry->d_name;
+
+        if (lchown(file_path.c_str(), uid, gid) < 0) {
+            PLOG(ERROR) << "lchown failed for " << file_path;
+            goto err;
+        }
+
+        if (fchmodat(AT_FDCWD, file_path.c_str(), mode, AT_SYMLINK_NOFOLLOW) != 0) {
+            PLOG(ERROR) << "fchmodat failed for " << file_path;
+            goto err;
+        }
     }
 
     return true;
+err:
+    int saved_errno = errno;
+    rmdir(path.c_str());
+    errno = saved_errno;
+
+    return false;
 }
 
 // Returns number of processes killed on success
@@ -302,17 +344,9 @@
 
 static int KillProcessGroup(uid_t uid, int initialPid, int signal, int retries,
                             int* max_processes) {
-    std::string cpuacct_path;
-    std::string memory_path;
-
-    CgroupGetControllerPath("cpuacct", &cpuacct_path);
-    CgroupGetControllerPath("memory", &memory_path);
-    memory_path += "/apps";
-
-    const char* cgroup =
-            (!access(ConvertUidPidToPath(cpuacct_path.c_str(), uid, initialPid).c_str(), F_OK))
-                    ? cpuacct_path.c_str()
-                    : memory_path.c_str();
+    std::string hierarchy_root_path;
+    CgroupGetControllerPath(CGROUPV2_CONTROLLER_NAME, &hierarchy_root_path);
+    const char* cgroup = hierarchy_root_path.c_str();
 
     std::chrono::steady_clock::time_point start = std::chrono::steady_clock::now();
 
@@ -355,7 +389,17 @@
             LOG(INFO) << "Successfully killed process cgroup uid " << uid << " pid " << initialPid
                       << " in " << static_cast<int>(ms) << "ms";
         }
-        return RemoveProcessGroup(cgroup, uid, initialPid);
+
+        int err = RemoveProcessGroup(cgroup, uid, initialPid, retries);
+
+        if (isMemoryCgroupSupported() && UsePerAppMemcg()) {
+            std::string memory_path;
+            CgroupGetControllerPath("memory", &memory_path);
+            memory_path += "/apps";
+            if (RemoveProcessGroup(memory_path.c_str(), uid, initialPid, retries)) return -1;
+        }
+
+        return err;
     } else {
         if (retries > 0) {
             LOG(ERROR) << "Failed to kill process cgroup uid " << uid << " pid " << initialPid
@@ -374,25 +418,30 @@
     return KillProcessGroup(uid, initialPid, signal, 0 /*retries*/, max_processes);
 }
 
-int createProcessGroup(uid_t uid, int initialPid, bool memControl) {
-    std::string cgroup;
-    if (isMemoryCgroupSupported() && (memControl || UsePerAppMemcg())) {
-        CgroupGetControllerPath("memory", &cgroup);
-        cgroup += "/apps";
-    } else {
-        CgroupGetControllerPath("cpuacct", &cgroup);
-    }
-
+static int createProcessGroupInternal(uid_t uid, int initialPid, std::string cgroup) {
     auto uid_path = ConvertUidToPath(cgroup.c_str(), uid);
 
-    if (!MkdirAndChown(uid_path, 0750, AID_SYSTEM, AID_SYSTEM)) {
+    struct stat cgroup_stat;
+    mode_t cgroup_mode = 0750;
+    gid_t cgroup_uid = AID_SYSTEM;
+    uid_t cgroup_gid = AID_SYSTEM;
+
+    if (stat(cgroup.c_str(), &cgroup_stat) == 1) {
+        PLOG(ERROR) << "Failed to get stats for " << cgroup;
+    } else {
+        cgroup_mode = cgroup_stat.st_mode;
+        cgroup_uid = cgroup_stat.st_uid;
+        cgroup_gid = cgroup_stat.st_gid;
+    }
+
+    if (!MkdirAndChown(uid_path, cgroup_mode, cgroup_uid, cgroup_gid)) {
         PLOG(ERROR) << "Failed to make and chown " << uid_path;
         return -errno;
     }
 
     auto uid_pid_path = ConvertUidPidToPath(cgroup.c_str(), uid, initialPid);
 
-    if (!MkdirAndChown(uid_pid_path, 0750, AID_SYSTEM, AID_SYSTEM)) {
+    if (!MkdirAndChown(uid_pid_path, cgroup_mode, cgroup_uid, cgroup_gid)) {
         PLOG(ERROR) << "Failed to make and chown " << uid_pid_path;
         return -errno;
     }
@@ -408,6 +457,27 @@
     return ret;
 }
 
+int createProcessGroup(uid_t uid, int initialPid, bool memControl) {
+    std::string cgroup;
+
+    if (memControl && !UsePerAppMemcg()) {
+        PLOG(ERROR) << "service memory controls are used without per-process memory cgroup support";
+        return -EINVAL;
+    }
+
+    if (isMemoryCgroupSupported() && UsePerAppMemcg()) {
+        CgroupGetControllerPath("memory", &cgroup);
+        cgroup += "/apps";
+        int ret = createProcessGroupInternal(uid, initialPid, cgroup);
+        if (ret != 0) {
+            return ret;
+        }
+    }
+
+    CgroupGetControllerPath(CGROUPV2_CONTROLLER_NAME, &cgroup);
+    return createProcessGroupInternal(uid, initialPid, cgroup);
+}
+
 static bool SetProcessGroupValue(int tid, const std::string& attr_name, int64_t value) {
     if (!isMemoryCgroupSupported()) {
         PLOG(ERROR) << "Memcg is not mounted.";
diff --git a/libprocessgroup/profiles/cgroups.json b/libprocessgroup/profiles/cgroups.json
index 5b7a28a..7bcb94b 100644
--- a/libprocessgroup/profiles/cgroups.json
+++ b/libprocessgroup/profiles/cgroups.json
@@ -15,11 +15,6 @@
       "GID": "system"
     },
     {
-      "Controller": "cpuacct",
-      "Path": "/acct",
-      "Mode": "0555"
-    },
-    {
       "Controller": "cpuset",
       "Path": "/dev/cpuset",
       "Mode": "0755",
diff --git a/libprocessgroup/profiles/cgroups.recovery.json b/libprocessgroup/profiles/cgroups.recovery.json
index f0bf5fd..e275252 100644
--- a/libprocessgroup/profiles/cgroups.recovery.json
+++ b/libprocessgroup/profiles/cgroups.recovery.json
@@ -1,9 +1,8 @@
 {
-  "Cgroups": [
-    {
-      "Controller": "cpuacct",
-      "Path": "/acct",
-      "Mode": "0555"
-    }
-  ]
+  "Cgroups2": {
+    "Path": "/sys/fs/cgroup",
+    "Mode": "0755",
+    "UID": "root",
+    "GID": "root"
+  }
 }
diff --git a/rootdir/init.rc b/rootdir/init.rc
index 3cabecc..863cf6c 100644
--- a/rootdir/init.rc
+++ b/rootdir/init.rc
@@ -655,6 +655,7 @@
     mkdir /data/apex 0755 root system encryption=None
     mkdir /data/apex/active 0755 root system
     mkdir /data/apex/backup 0700 root system
+    mkdir /data/apex/decompressed 0700 root system encryption=Require
     mkdir /data/apex/hashtree 0700 root system
     mkdir /data/apex/sessions 0700 root system
     mkdir /data/app-staging 0751 system system encryption=DeleteIfNecessary
diff --git a/trusty/confirmationui/Android.bp b/trusty/confirmationui/Android.bp
index 60e0e71..09d48ad 100644
--- a/trusty/confirmationui/Android.bp
+++ b/trusty/confirmationui/Android.bp
@@ -54,6 +54,7 @@
         "android.hardware.confirmationui@1.0",
         "android.hardware.keymaster@4.0",
         "libbase",
+        "libdmabufheap",
         "libhidlbase",
         "libteeui_hal_support",
         "libtrusty",
@@ -92,4 +93,4 @@
         "-Werror",
         "-DTEEUI_USE_STD_VECTOR",
     ],
-}
\ No newline at end of file
+}
diff --git a/trusty/confirmationui/TrustyApp.cpp b/trusty/confirmationui/TrustyApp.cpp
index e4c68f9..0e84b19 100644
--- a/trusty/confirmationui/TrustyApp.cpp
+++ b/trusty/confirmationui/TrustyApp.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright 2020, The Android Open Source Project
+ * Copyright 2021, The Android Open Source Project
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -15,140 +15,155 @@
  */
 
 #include "TrustyApp.h"
+#include "TrustyIpc.h"
 
+#include <BufferAllocator/BufferAllocator.h>
 #include <android-base/logging.h>
+#include <sys/mman.h>
 #include <sys/uio.h>
 #include <trusty/tipc.h>
 
+#define countof(arr) (sizeof(arr) / sizeof(arr[0]))
+
 namespace android {
 namespace trusty {
 
-// 0x1000 is the message buffer size but we need to leave some space for a protocol header.
-// This assures that packets can always be read/written in one read/write operation.
-static constexpr const uint32_t kPacketSize = 0x1000 - 32;
+using ::android::base::unique_fd;
 
-enum class PacketType : uint32_t {
-    SND,
-    RCV,
-    ACK,
-};
-
-struct PacketHeader {
-    PacketType type;
-    uint32_t remaining;
-};
-
-const char* toString(PacketType t) {
-    switch (t) {
-    case PacketType::SND:
-        return "SND";
-    case PacketType::RCV:
-        return "RCV";
-    case PacketType::ACK:
-        return "ACK";
-    default:
-        return "UNKNOWN";
-    }
+static inline uintptr_t RoundPageUp(uintptr_t val) {
+    return (val + (PAGE_SIZE - 1)) & ~(PAGE_SIZE - 1);
 }
 
-static constexpr const uint32_t kHeaderSize = sizeof(PacketHeader);
-static constexpr const uint32_t kPayloadSize = kPacketSize - kHeaderSize;
+ssize_t TrustyApp::TrustyRpc(const uint8_t* obegin, const uint8_t* oend, uint8_t* ibegin,
+                             uint8_t* iend) {
+    uint32_t olen = oend - obegin;
 
-ssize_t TrustyRpc(int handle, const uint8_t* obegin, const uint8_t* oend, uint8_t* ibegin,
-                  uint8_t* iend) {
-    while (obegin != oend) {
-        PacketHeader header = {
-            .type = PacketType::SND,
-            .remaining = uint32_t(oend - obegin),
-        };
-        uint32_t body_size = std::min(kPayloadSize, header.remaining);
-        iovec iov[] = {
-            {
-                .iov_base = &header,
-                .iov_len = kHeaderSize,
-            },
-            {
-                .iov_base = const_cast<uint8_t*>(obegin),
-                .iov_len = body_size,
-            },
-        };
-        int rc = writev(handle, iov, 2);
-        if (!rc) {
-            PLOG(ERROR) << "Error sending SND message. " << rc;
-            return rc;
-        }
-
-        obegin += body_size;
-
-        rc = read(handle, &header, kHeaderSize);
-        if (!rc) {
-            PLOG(ERROR) << "Error reading ACK. " << rc;
-            return rc;
-        }
-
-        if (header.type != PacketType::ACK || header.remaining != oend - obegin) {
-            LOG(ERROR) << "malformed ACK";
-            return -1;
-        }
+    if (olen > shm_len_) {
+        LOG(ERROR) << AT << "request message too long to fit in shared memory";
+        return -1;
     }
 
-    ssize_t remaining = 0;
-    auto begin = ibegin;
-    do {
-        PacketHeader header = {
-            .type = PacketType::RCV,
-            .remaining = 0,
-        };
+    memcpy(shm_base_, obegin, olen);
 
-        iovec iov[] = {
-            {
-                .iov_base = &header,
-                .iov_len = kHeaderSize,
-            },
-            {
-                .iov_base = begin,
-                .iov_len = uint32_t(iend - begin),
-            },
-        };
+    confirmationui_hdr hdr = {
+        .cmd = CONFIRMATIONUI_CMD_MSG,
+    };
+    confirmationui_msg_args args = {
+        .msg_len = olen,
+    };
+    iovec iov[] = {
+        {
+            .iov_base = &hdr,
+            .iov_len = sizeof(hdr),
+        },
+        {
+            .iov_base = &args,
+            .iov_len = sizeof(args),
+        },
+    };
 
-        ssize_t rc = writev(handle, iov, 1);
-        if (!rc) {
-            PLOG(ERROR) << "Error sending RCV message. " << rc;
-            return rc;
-        }
+    int rc = tipc_send(handle_, iov, countof(iov), NULL, 0);
+    if (rc != static_cast<int>(sizeof(hdr) + sizeof(args))) {
+        LOG(ERROR) << AT << "failed to send MSG request";
+        return -1;
+    }
 
-        rc = readv(handle, iov, 2);
-        if (rc < 0) {
-            PLOG(ERROR) << "Error reading response. " << rc;
-            return rc;
-        }
+    rc = readv(handle_, iov, countof(iov));
+    if (rc != static_cast<int>(sizeof(hdr) + sizeof(args))) {
+        LOG(ERROR) << AT << "failed to receive MSG response";
+        return -1;
+    }
 
-        uint32_t body_size = std::min(kPayloadSize, header.remaining);
-        if (body_size != rc - kHeaderSize) {
-            LOG(ERROR) << "Unexpected amount of data: " << rc;
-            return -1;
-        }
+    if (hdr.cmd != (CONFIRMATIONUI_CMD_MSG | CONFIRMATIONUI_RESP_BIT)) {
+        LOG(ERROR) << AT << "unknown response command: " << hdr.cmd;
+        return -1;
+    }
 
-        remaining = header.remaining - body_size;
-        begin += body_size;
-    } while (remaining);
+    uint32_t ilen = iend - ibegin;
+    if (args.msg_len > ilen) {
+        LOG(ERROR) << AT << "response message too long to fit in return buffer";
+        return -1;
+    }
 
-    return begin - ibegin;
+    memcpy(ibegin, shm_base_, args.msg_len);
+
+    return args.msg_len;
 }
 
 TrustyApp::TrustyApp(const std::string& path, const std::string& appname)
     : handle_(kInvalidHandle) {
-    handle_ = tipc_connect(path.c_str(), appname.c_str());
-    if (handle_ == kInvalidHandle) {
+    unique_fd tipc_handle(tipc_connect(path.c_str(), appname.c_str()));
+    if (tipc_handle < 0) {
         LOG(ERROR) << AT << "failed to connect to Trusty TA \"" << appname << "\" using dev:"
                    << "\"" << path << "\"";
+        return;
     }
+
+    uint32_t shm_len = RoundPageUp(CONFIRMATIONUI_MAX_MSG_SIZE);
+    BufferAllocator allocator;
+    unique_fd dma_buf(allocator.Alloc("system", shm_len));
+    if (dma_buf < 0) {
+        LOG(ERROR) << AT << "failed to allocate shared memory buffer";
+        return;
+    }
+
+    if (dma_buf < 0) {
+        LOG(ERROR) << AT << "failed to allocate shared memory buffer";
+        return;
+    }
+
+    confirmationui_hdr hdr = {
+        .cmd = CONFIRMATIONUI_CMD_INIT,
+    };
+    confirmationui_init_req args = {
+        .shm_len = shm_len,
+    };
+    iovec iov[] = {
+        {
+            .iov_base = &hdr,
+            .iov_len = sizeof(hdr),
+        },
+        {
+            .iov_base = &args,
+            .iov_len = sizeof(args),
+        },
+    };
+    trusty_shm shm = {
+        .fd = dma_buf,
+        .transfer = TRUSTY_SHARE,
+    };
+
+    int rc = tipc_send(tipc_handle, iov, 2, &shm, 1);
+    if (rc != static_cast<int>(sizeof(hdr) + sizeof(args))) {
+        LOG(ERROR) << AT << "failed to send INIT request";
+        return;
+    }
+
+    rc = read(tipc_handle, &hdr, sizeof(hdr));
+    if (rc != static_cast<int>(sizeof(hdr))) {
+        LOG(ERROR) << AT << "failed to receive INIT response";
+        return;
+    }
+
+    if (hdr.cmd != (CONFIRMATIONUI_CMD_INIT | CONFIRMATIONUI_RESP_BIT)) {
+        LOG(ERROR) << AT << "unknown response command: " << hdr.cmd;
+        return;
+    }
+
+    void* shm_base = mmap(0, shm_len, PROT_READ | PROT_WRITE, MAP_SHARED, dma_buf, 0);
+    if (shm_base == MAP_FAILED) {
+        LOG(ERROR) << AT << "failed to mmap() shared memory buffer";
+        return;
+    }
+
+    handle_ = std::move(tipc_handle);
+    shm_base_ = shm_base;
+    shm_len_ = shm_len;
+
     LOG(INFO) << AT << "succeeded to connect to Trusty TA \"" << appname << "\"";
 }
+
 TrustyApp::~TrustyApp() {
-    if (handle_ != kInvalidHandle) {
-        tipc_close(handle_);
-    }
     LOG(INFO) << "Done shutting down TrustyApp";
 }
 
diff --git a/trusty/confirmationui/TrustyApp.h b/trusty/confirmationui/TrustyApp.h
index 05a25f6..406f439 100644
--- a/trusty/confirmationui/TrustyApp.h
+++ b/trusty/confirmationui/TrustyApp.h
@@ -16,7 +16,10 @@
 
 #pragma once
 
+#include "TrustyIpc.h"
+
 #include <android-base/logging.h>
+#include <android-base/unique_fd.h>
 #include <errno.h>
 #include <poll.h>
 #include <stdio.h>
@@ -60,19 +63,11 @@
     MSG_TOO_LONG = -2,
 };
 
-/*
- * There is a hard limitation of 0x1800 bytes for the to-be-signed message size. The protocol
- * overhead is limited, so that 0x2000 is a buffer size that will be sufficient in any benign
- * mode of operation.
- */
-static constexpr const size_t kSendBufferSize = 0x2000;
-
-ssize_t TrustyRpc(int handle, const uint8_t* obegin, const uint8_t* oend, uint8_t* ibegin,
-                  uint8_t* iend);
-
 class TrustyApp {
   private:
-    int handle_;
+    android::base::unique_fd handle_;
+    void* shm_base_;
+    size_t shm_len_;
     static constexpr const int kInvalidHandle = -1;
     /*
      * This mutex serializes communication with the trusted app, not handle_.
@@ -84,6 +79,8 @@
     TrustyApp(const std::string& path, const std::string& appname);
     ~TrustyApp();
 
+    ssize_t TrustyRpc(const uint8_t* obegin, const uint8_t* oend, uint8_t* ibegin, uint8_t* iend);
+
     template <typename Request, typename Response, typename... T>
     std::tuple<TrustyAppError, msg2tuple_t<Response>> issueCmd(const T&... args) {
         std::lock_guard<std::mutex> lock(mutex_);
@@ -93,7 +90,7 @@
             return {TrustyAppError::ERROR, {}};
         }
 
-        uint8_t buffer[kSendBufferSize];
+        uint8_t buffer[CONFIRMATIONUI_MAX_MSG_SIZE];
         WriteStream out(buffer);
 
         out = write(Request(), out, args...);
@@ -102,8 +99,8 @@
             return {TrustyAppError::MSG_TOO_LONG, {}};
         }
 
-        auto rc = TrustyRpc(handle_, &buffer[0], const_cast<const uint8_t*>(out.pos()), &buffer[0],
-                            &buffer[kSendBufferSize]);
+        auto rc = TrustyRpc(&buffer[0], const_cast<const uint8_t*>(out.pos()), &buffer[0],
+                            &buffer[CONFIRMATIONUI_MAX_MSG_SIZE]);
         if (rc < 0) return {TrustyAppError::ERROR, {}};
 
         ReadStream in(&buffer[0], rc);
@@ -125,7 +122,7 @@
             return TrustyAppError::ERROR;
         }
 
-        uint8_t buffer[kSendBufferSize];
+        uint8_t buffer[CONFIRMATIONUI_MAX_MSG_SIZE];
         WriteStream out(buffer);
 
         out = write(Request(), out, args...);
@@ -134,8 +131,8 @@
             return TrustyAppError::MSG_TOO_LONG;
         }
 
-        auto rc = TrustyRpc(handle_, &buffer[0], const_cast<const uint8_t*>(out.pos()), &buffer[0],
-                            &buffer[kSendBufferSize]);
+        auto rc = TrustyRpc(&buffer[0], const_cast<const uint8_t*>(out.pos()), &buffer[0],
+                            &buffer[CONFIRMATIONUI_MAX_MSG_SIZE]);
         if (rc < 0) {
             LOG(ERROR) << "send command failed: " << strerror(errno) << " (" << errno << ")";
             return TrustyAppError::ERROR;
diff --git a/trusty/confirmationui/TrustyConfirmationUI.cpp b/trusty/confirmationui/TrustyConfirmationUI.cpp
index 6b25893..c8b24e3 100644
--- a/trusty/confirmationui/TrustyConfirmationUI.cpp
+++ b/trusty/confirmationui/TrustyConfirmationUI.cpp
@@ -71,7 +71,7 @@
 using TeeuiRc = ::teeui::ResponseCode;
 
 constexpr const char kTrustyDeviceName[] = "/dev/trusty-ipc-dev0";
-constexpr const char kConfirmationuiAppName[] = "com.android.trusty.confirmationui";
+constexpr const char kConfirmationuiAppName[] = CONFIRMATIONUI_PORT;
 
 namespace {
 
diff --git a/trusty/confirmationui/TrustyIpc.h b/trusty/confirmationui/TrustyIpc.h
new file mode 100644
index 0000000..eb764bc
--- /dev/null
+++ b/trusty/confirmationui/TrustyIpc.h
@@ -0,0 +1,80 @@
+/*
+ * Copyright 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#pragma once
+
+#include <stdint.h>
+
+/*
+ * This interface is shared between Android and Trusty. There is a copy in each
+ * repository. They must be kept in sync.
+ */
+
+#define CONFIRMATIONUI_PORT "com.android.trusty.confirmationui"
+
+/**
+ * enum confirmationui_cmd - command identifiers for ConfirmationUI interface
+ * @CONFIRMATIONUI_RESP_BIT:  response bit set as part of response
+ * @CONFIRMATIONUI_REQ_SHIFT: number of bits used by response bit
+ * @CONFIRMATIONUI_CMD_INIT:  command to initialize session
+ * @CONFIRMATIONUI_CMD_MSG:   command to send ConfirmationUI messages
+ */
+enum confirmationui_cmd : uint32_t {
+    CONFIRMATIONUI_RESP_BIT = 1,
+    CONFIRMATIONUI_REQ_SHIFT = 1,
+
+    CONFIRMATIONUI_CMD_INIT = (1 << CONFIRMATIONUI_REQ_SHIFT),
+    CONFIRMATIONUI_CMD_MSG = (2 << CONFIRMATIONUI_REQ_SHIFT),
+};
+
+/**
+ * struct confirmationui_hdr - header for ConfirmationUI messages
+ * @cmd: command identifier
+ *
+ * Note that no messages return a status code. Any error on the server side
+ * results in the connection being closed. So, operations can be assumed to be
+ * successful if they return a response.
+ */
+struct confirmationui_hdr {
+    uint32_t cmd;
+};
+
+/**
+ * struct confirmationui_init_req - arguments for request to initialize a
+ *                                  session
+ * @shm_len: length of memory region being shared
+ *
+ * A handle to a memory region must be sent along with this message. This memory
+ * is send to ConfirmationUI messages.
+ */
+struct confirmationui_init_req {
+    uint32_t shm_len;
+};
+
+/**
+ * struct confirmationui_msg_args - arguments for sending a message
+ * @msg_len: length of message being sent
+ *
+ * Contents of the message are located in the shared memory region that is
+ * established using %CONFIRMATIONUI_CMD_INIT.
+ *
+ * ConfirmationUI messages can travel both ways.
+ */
+struct confirmationui_msg_args {
+    uint32_t msg_len;
+};
+
+#define CONFIRMATIONUI_MAX_MSG_SIZE 0x2000
diff --git a/trusty/confirmationui/android.hardware.confirmationui@1.0-service.trusty.rc b/trusty/confirmationui/android.hardware.confirmationui@1.0-service.trusty.rc
index dc7a03b..3ba6fc0 100644
--- a/trusty/confirmationui/android.hardware.confirmationui@1.0-service.trusty.rc
+++ b/trusty/confirmationui/android.hardware.confirmationui@1.0-service.trusty.rc
@@ -1,4 +1,4 @@
 service confirmationui-1-0 /vendor/bin/hw/android.hardware.confirmationui@1.0-service.trusty
     class hal
-    user nobody
-    group drmrpc input
+    user system
+    group drmrpc input system
diff --git a/trusty/coverage/coverage.cpp b/trusty/coverage/coverage.cpp
index 5eccdc5..3c6b5c5 100644
--- a/trusty/coverage/coverage.cpp
+++ b/trusty/coverage/coverage.cpp
@@ -29,6 +29,7 @@
 #include <trusty/coverage/record.h>
 #include <trusty/coverage/tipc.h>
 #include <trusty/tipc.h>
+#include <iostream>
 
 #define COVERAGE_CLIENT_PORT "com.android.trusty.coverage.client"
 
@@ -122,7 +123,9 @@
 
     int fd = tipc_connect(tipc_dev_.c_str(), COVERAGE_CLIENT_PORT);
     if (fd < 0) {
-        return ErrnoError() << "failed to connect to Trusty coverarge server: ";
+        // Don't error out to support fuzzing builds without coverage, e.g. for repros.
+        std::cerr << "WARNING!!! Failed to connect to Trusty coverarge server." << std::endl;
+        return {};
     }
     coverage_srv_fd_.reset(fd);
 
@@ -130,7 +133,7 @@
     req.open_args.uuid = uuid_;
     auto ret = Rpc(&req, -1, &resp);
     if (!ret.ok()) {
-        return Error() << "failed to open coverage client: ";
+        return Error() << "failed to open coverage client: " << ret.error();
     }
     record_len_ = resp.open_args.record_len;
     shm_len_ = RoundPageUp(record_len_);
@@ -153,13 +156,17 @@
     req.share_record_args.shm_len = shm_len_;
     ret = Rpc(&req, dma_buf, &resp);
     if (!ret.ok()) {
-        return Error() << "failed to send shared memory: ";
+        return Error() << "failed to send shared memory: " << ret.error();
     }
 
     shm_ = shm;
     return {};
 }
 
+bool CoverageRecord::IsOpen() {
+    return shm_;
+}
+
 void CoverageRecord::ResetFullRecord() {
     auto header_region = GetRegionBounds(COV_START);
     if (!header_region.ok()) {
diff --git a/trusty/coverage/include/trusty/coverage/coverage.h b/trusty/coverage/include/trusty/coverage/coverage.h
index 5da68da..9ccc981 100644
--- a/trusty/coverage/include/trusty/coverage/coverage.h
+++ b/trusty/coverage/include/trusty/coverage/coverage.h
@@ -47,6 +47,7 @@
 
     ~CoverageRecord();
     Result<void> Open();
+    bool IsOpen();
     void ResetFullRecord();
     void ResetCounts();
     void ResetPCs();
diff --git a/trusty/fuzz/counters.cpp b/trusty/fuzz/counters.cpp
index 1e863ac..4d34059 100644
--- a/trusty/fuzz/counters.cpp
+++ b/trusty/fuzz/counters.cpp
@@ -41,6 +41,10 @@
 namespace fuzz {
 
 ExtraCounters::ExtraCounters(coverage::CoverageRecord* record) : record_(record) {
+    if (!record_->IsOpen()) {
+        return;
+    }
+
     assert(fuzzer::ExtraCountersBegin());
     assert(fuzzer::ExtraCountersEnd());
 
@@ -51,10 +55,18 @@
 }
 
 ExtraCounters::~ExtraCounters() {
+    if (!record_->IsOpen()) {
+        return;
+    }
+
     Flush();
 }
 
 void ExtraCounters::Reset() {
+    if (!record_->IsOpen()) {
+        return;
+    }
+
     record_->ResetCounts();
     fuzzer::ClearExtraCounters();
 }
diff --git a/trusty/fuzz/utils.cpp b/trusty/fuzz/utils.cpp
index f4cf0b6..3526337 100644
--- a/trusty/fuzz/utils.cpp
+++ b/trusty/fuzz/utils.cpp
@@ -113,7 +113,7 @@
     int rc = write(ta_fd_, buf, len);
     alarm(0);
     if (rc < 0) {
-        return Error() << "failed to read TIPC message from TA: ";
+        return Error() << "failed to write TIPC message to TA: ";
     }
 
     return {};