diff --git a/adb/Android.bp b/adb/Android.bp
index 6fd0767..2f71945 100644
--- a/adb/Android.bp
+++ b/adb/Android.bp
@@ -298,6 +298,7 @@
         "client/fastdeploycallbacks.cpp",
         "client/incremental.cpp",
         "client/incremental_server.cpp",
+        "client/incremental_utils.cpp",
         "shell_service_protocol.cpp",
     ],
 
diff --git a/adb/client/incremental_server.cpp b/adb/client/incremental_server.cpp
index 6c36a0f..1f47de8 100644
--- a/adb/client/incremental_server.cpp
+++ b/adb/client/incremental_server.cpp
@@ -39,6 +39,7 @@
 #include "adb_trace.h"
 #include "adb_unique_fd.h"
 #include "adb_utils.h"
+#include "incremental_utils.h"
 #include "sysdeps.h"
 
 namespace incremental {
@@ -136,6 +137,7 @@
     // Plain file
     File(const char* filepath, FileId id, int64_t size, unique_fd fd) : File(filepath, id, size) {
         this->fd_ = std::move(fd);
+        priority_blocks_ = PriorityBlocksForFile(filepath, fd_.get(), size);
     }
     int64_t ReadBlock(BlockIdx block_idx, void* buf, bool* is_zip_compressed,
                       std::string* error) const {
@@ -147,6 +149,7 @@
     }
 
     const unique_fd& RawFd() const { return fd_; }
+    const std::vector<BlockIdx>& PriorityBlocks() const { return priority_blocks_; }
 
     std::vector<bool> sentBlocks;
     NumBlocks sentBlocksCount = 0;
@@ -160,6 +163,7 @@
         sentBlocks.resize(numBytesToNumBlocks(size));
     }
     unique_fd fd_;
+    std::vector<BlockIdx> priority_blocks_;
 };
 
 class IncrementalServer {
@@ -176,14 +180,23 @@
         const File* file;
         BlockIdx overallIndex = 0;
         BlockIdx overallEnd = 0;
+        BlockIdx priorityIndex = 0;
 
-        PrefetchState(const File& f) : file(&f), overallEnd((BlockIdx)f.sentBlocks.size()) {}
-        PrefetchState(const File& f, BlockIdx start, int count)
+        explicit PrefetchState(const File& f, BlockIdx start, int count)
             : file(&f),
               overallIndex(start),
               overallEnd(std::min<BlockIdx>(start + count, f.sentBlocks.size())) {}
 
-        bool done() const { return overallIndex >= overallEnd; }
+        explicit PrefetchState(const File& f)
+            : PrefetchState(f, 0, (BlockIdx)f.sentBlocks.size()) {}
+
+        bool done() const {
+            const bool overallSent = (overallIndex >= overallEnd);
+            if (file->PriorityBlocks().empty()) {
+                return overallSent;
+            }
+            return overallSent && (priorityIndex >= (BlockIdx)file->PriorityBlocks().size());
+        }
     };
 
     bool SkipToRequest(void* buffer, size_t* size, bool blocking);
@@ -365,6 +378,17 @@
     while (!prefetches_.empty() && blocksToSend > 0) {
         auto& prefetch = prefetches_.front();
         const auto& file = *prefetch.file;
+        const auto& priority_blocks = file.PriorityBlocks();
+        if (!priority_blocks.empty()) {
+            for (auto& i = prefetch.priorityIndex;
+                 blocksToSend > 0 && i < (BlockIdx)priority_blocks.size(); ++i) {
+                if (auto res = SendBlock(file.id, priority_blocks[i]); res == SendResult::Sent) {
+                    --blocksToSend;
+                } else if (res == SendResult::Error) {
+                    fprintf(stderr, "Failed to send priority block %" PRId32 "\n", i);
+                }
+            }
+        }
         for (auto& i = prefetch.overallIndex; blocksToSend > 0 && i < prefetch.overallEnd; ++i) {
             if (auto res = SendBlock(file.id, i); res == SendResult::Sent) {
                 --blocksToSend;
diff --git a/adb/client/incremental_utils.cpp b/adb/client/incremental_utils.cpp
new file mode 100644
index 0000000..316480c
--- /dev/null
+++ b/adb/client/incremental_utils.cpp
@@ -0,0 +1,216 @@
+/*
+ * Copyright (C) 2020 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.
+ */
+
+#define TRACE_TAG INCREMENTAL
+
+#include "incremental_utils.h"
+
+#include <android-base/strings.h>
+#include <ziparchive/zip_archive.h>
+#include <ziparchive/zip_writer.h>
+
+#include <cinttypes>
+#include <numeric>
+#include <unordered_set>
+
+#include "sysdeps.h"
+
+static constexpr int kBlockSize = 4096;
+
+static constexpr inline int32_t offsetToBlockIndex(int64_t offset) {
+    return (offset & ~(kBlockSize - 1)) >> 12;
+}
+
+template <class T>
+T valueAt(int fd, off64_t offset) {
+    T t;
+    memset(&t, 0, sizeof(T));
+    if (adb_pread(fd, &t, sizeof(T), offset) != sizeof(T)) {
+        memset(&t, -1, sizeof(T));
+    }
+
+    return t;
+}
+
+static void appendBlocks(int32_t start, int count, std::vector<int32_t>* blocks) {
+    if (count == 1) {
+        blocks->push_back(start);
+    } else {
+        auto oldSize = blocks->size();
+        blocks->resize(oldSize + count);
+        std::iota(blocks->begin() + oldSize, blocks->end(), start);
+    }
+}
+
+template <class T>
+static void unduplicate(std::vector<T>& v) {
+    std::unordered_set<T> uniques(v.size());
+    v.erase(std::remove_if(v.begin(), v.end(),
+                           [&uniques](T t) { return !uniques.insert(t).second; }),
+            v.end());
+}
+
+static off64_t CentralDirOffset(int fd, int64_t fileSize) {
+    static constexpr int kZipEocdRecMinSize = 22;
+    static constexpr int32_t kZipEocdRecSig = 0x06054b50;
+    static constexpr int kZipEocdCentralDirSizeFieldOffset = 12;
+    static constexpr int kZipEocdCommentLengthFieldOffset = 20;
+
+    int32_t sigBuf = 0;
+    off64_t eocdOffset = -1;
+    off64_t maxEocdOffset = fileSize - kZipEocdRecMinSize;
+    int16_t commentLenBuf = 0;
+
+    // Search from the end of zip, backward to find beginning of EOCD
+    for (int16_t commentLen = 0; commentLen < fileSize; ++commentLen) {
+        sigBuf = valueAt<int32_t>(fd, maxEocdOffset - commentLen);
+        if (sigBuf == kZipEocdRecSig) {
+            commentLenBuf = valueAt<int16_t>(
+                    fd, maxEocdOffset - commentLen + kZipEocdCommentLengthFieldOffset);
+            if (commentLenBuf == commentLen) {
+                eocdOffset = maxEocdOffset - commentLen;
+                break;
+            }
+        }
+    }
+
+    if (eocdOffset < 0) {
+        return -1;
+    }
+
+    off64_t cdLen = static_cast<int64_t>(
+            valueAt<int32_t>(fd, eocdOffset + kZipEocdCentralDirSizeFieldOffset));
+
+    return eocdOffset - cdLen;
+}
+
+// Does not support APKs larger than 4GB
+static off64_t SignerBlockOffset(int fd, int64_t fileSize) {
+    static constexpr int kApkSigBlockMinSize = 32;
+    static constexpr int kApkSigBlockFooterSize = 24;
+    static constexpr int64_t APK_SIG_BLOCK_MAGIC_HI = 0x3234206b636f6c42l;
+    static constexpr int64_t APK_SIG_BLOCK_MAGIC_LO = 0x20676953204b5041l;
+
+    off64_t cdOffset = CentralDirOffset(fd, fileSize);
+    if (cdOffset < 0) {
+        return -1;
+    }
+    // CD offset is where original signer block ends. Search backwards for magic and footer.
+    if (cdOffset < kApkSigBlockMinSize ||
+        valueAt<int64_t>(fd, cdOffset - 2 * sizeof(int64_t)) != APK_SIG_BLOCK_MAGIC_LO ||
+        valueAt<int64_t>(fd, cdOffset - sizeof(int64_t)) != APK_SIG_BLOCK_MAGIC_HI) {
+        return -1;
+    }
+    int32_t signerSizeInFooter = valueAt<int32_t>(fd, cdOffset - kApkSigBlockFooterSize);
+    off64_t signerBlockOffset = cdOffset - signerSizeInFooter - sizeof(int64_t);
+    if (signerBlockOffset < 0) {
+        return -1;
+    }
+    int32_t signerSizeInHeader = valueAt<int32_t>(fd, signerBlockOffset);
+    if (signerSizeInFooter != signerSizeInHeader) {
+        return -1;
+    }
+
+    return signerBlockOffset;
+}
+
+static std::vector<int32_t> ZipPriorityBlocks(off64_t signerBlockOffset, int64_t fileSize) {
+    int32_t signerBlockIndex = offsetToBlockIndex(signerBlockOffset);
+    int32_t lastBlockIndex = offsetToBlockIndex(fileSize);
+    const auto numPriorityBlocks = lastBlockIndex - signerBlockIndex + 1;
+
+    std::vector<int32_t> zipPriorityBlocks;
+
+    // Some magic here: most of zip libraries perform a scan for EOCD record starting at the offset
+    // of a maximum comment size from the end of the file. This means the last 65-ish KBs will be
+    // accessed first, followed by the rest of the central directory blocks. Make sure we
+    // send the data in the proper order, as central directory can be quite big by itself.
+    static constexpr auto kMaxZipCommentSize = 64 * 1024;
+    static constexpr auto kNumBlocksInEocdSearch = kMaxZipCommentSize / kBlockSize + 1;
+    if (numPriorityBlocks > kNumBlocksInEocdSearch) {
+        appendBlocks(lastBlockIndex - kNumBlocksInEocdSearch + 1, kNumBlocksInEocdSearch,
+                     &zipPriorityBlocks);
+        appendBlocks(signerBlockIndex, numPriorityBlocks - kNumBlocksInEocdSearch,
+                     &zipPriorityBlocks);
+    } else {
+        appendBlocks(signerBlockIndex, numPriorityBlocks, &zipPriorityBlocks);
+    }
+
+    // Somehow someone keeps accessing the start of the archive, even if there's nothing really
+    // interesting there...
+    appendBlocks(0, 1, &zipPriorityBlocks);
+    return zipPriorityBlocks;
+}
+
+// TODO(b/151676293): avoid using OpenArchiveFd that reads local file headers
+// which causes additional performance cost. Instead, only read from central directory.
+static std::vector<int32_t> InstallationPriorityBlocks(int fd, int64_t fileSize) {
+    std::vector<int32_t> installationPriorityBlocks;
+    ZipArchiveHandle zip;
+    if (OpenArchiveFd(fd, "", &zip, false) != 0) {
+        return {};
+    }
+    void* cookie = nullptr;
+    if (StartIteration(zip, &cookie) != 0) {
+        return {};
+    }
+    ZipEntry entry;
+    std::string_view entryName;
+    while (Next(cookie, &entry, &entryName) == 0) {
+        if (entryName == "resources.arsc" || entryName == "AndroidManifest.xml" ||
+            entryName.starts_with("lib/")) {
+            // Full entries are needed for installation
+            off64_t entryStartOffset = entry.offset;
+            off64_t entryEndOffset =
+                    entryStartOffset +
+                    (entry.method == kCompressStored ? entry.uncompressed_length
+                                                     : entry.compressed_length) +
+                    (entry.has_data_descriptor ? 16 /* sizeof(DataDescriptor) */ : 0);
+            int32_t startBlockIndex = offsetToBlockIndex(entryStartOffset);
+            int32_t endBlockIndex = offsetToBlockIndex(entryEndOffset);
+            int32_t numNewBlocks = endBlockIndex - startBlockIndex + 1;
+            appendBlocks(startBlockIndex, numNewBlocks, &installationPriorityBlocks);
+        } else if (entryName == "classes.dex") {
+            // Only the head is needed for installation
+            int32_t startBlockIndex = offsetToBlockIndex(entry.offset);
+            appendBlocks(startBlockIndex, 1, &installationPriorityBlocks);
+        }
+    }
+
+    EndIteration(cookie);
+    CloseArchive(zip);
+    return installationPriorityBlocks;
+}
+
+namespace incremental {
+std::vector<int32_t> PriorityBlocksForFile(const std::string& filepath, int fd, int64_t fileSize) {
+    if (!android::base::EndsWithIgnoreCase(filepath, ".apk")) {
+        return {};
+    }
+    off64_t signerOffset = SignerBlockOffset(fd, fileSize);
+    if (signerOffset < 0) {
+        // No signer block? not a valid APK
+        return {};
+    }
+    std::vector<int32_t> priorityBlocks = ZipPriorityBlocks(signerOffset, fileSize);
+    std::vector<int32_t> installationPriorityBlocks = InstallationPriorityBlocks(fd, fileSize);
+
+    priorityBlocks.insert(priorityBlocks.end(), installationPriorityBlocks.begin(),
+                          installationPriorityBlocks.end());
+    unduplicate(priorityBlocks);
+    return priorityBlocks;
+}
+}  // namespace incremental
\ No newline at end of file
diff --git a/adb/client/incremental_utils.h b/adb/client/incremental_utils.h
new file mode 100644
index 0000000..8bcf6c0
--- /dev/null
+++ b/adb/client/incremental_utils.h
@@ -0,0 +1,26 @@
+/*
+ * Copyright (C) 2020 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>
+
+#include <string>
+#include <vector>
+
+namespace incremental {
+std::vector<int32_t> PriorityBlocksForFile(const std::string& filepath, int fd, int64_t fileSize);
+}  // namespace incremental
\ No newline at end of file