diff --git a/adb/client/commandline.cpp b/adb/client/commandline.cpp
index 6e143c1..e38e305 100644
--- a/adb/client/commandline.cpp
+++ b/adb/client/commandline.cpp
@@ -841,14 +841,19 @@
         return -1;
     }
 
-    std::string service = android::base::StringPrintf(
-        "sideload-host:%d:%d", static_cast<int>(sb.st_size), SIDELOAD_HOST_BLOCK_SIZE);
+    std::string service =
+            android::base::StringPrintf("sideload-host:%" PRId64 ":%d",
+                                        static_cast<int64_t>(sb.st_size), SIDELOAD_HOST_BLOCK_SIZE);
     std::string error;
     unique_fd device_fd(adb_connect(service, &error));
     if (device_fd < 0) {
-        // Try falling back to the older (<= K) sideload method. Maybe this
-        // is an older device that doesn't support sideload-host.
         fprintf(stderr, "adb: sideload connection failed: %s\n", error.c_str());
+
+        // If this is a small enough package, maybe this is an older device that doesn't
+        // support sideload-host. Try falling back to the older (<= K) sideload method.
+        if (sb.st_size > INT_MAX) {
+            return -1;
+        }
         fprintf(stderr, "adb: trying pre-KitKat sideload method...\n");
         return adb_sideload_legacy(filename, package_fd, static_cast<int>(sb.st_size));
     }
@@ -858,7 +863,7 @@
 
     char buf[SIDELOAD_HOST_BLOCK_SIZE];
 
-    size_t xfer = 0;
+    int64_t xfer = 0;
     int last_percent = -1;
     while (true) {
         if (!ReadFdExactly(device_fd, buf, 8)) {
@@ -874,20 +879,22 @@
             return 0;
         }
 
-        int block = strtol(buf, nullptr, 10);
-
-        size_t offset = block * SIDELOAD_HOST_BLOCK_SIZE;
-        if (offset >= static_cast<size_t>(sb.st_size)) {
-            fprintf(stderr, "adb: failed to read block %d past end\n", block);
+        int64_t block = strtoll(buf, nullptr, 10);
+        int64_t offset = block * SIDELOAD_HOST_BLOCK_SIZE;
+        if (offset >= static_cast<int64_t>(sb.st_size)) {
+            fprintf(stderr,
+                    "adb: failed to read block %" PRId64 " at offset %" PRId64 ", past end %" PRId64
+                    "\n",
+                    block, offset, static_cast<int64_t>(sb.st_size));
             return -1;
         }
 
         size_t to_write = SIDELOAD_HOST_BLOCK_SIZE;
-        if ((offset + SIDELOAD_HOST_BLOCK_SIZE) > static_cast<size_t>(sb.st_size)) {
+        if ((offset + SIDELOAD_HOST_BLOCK_SIZE) > static_cast<int64_t>(sb.st_size)) {
             to_write = sb.st_size - offset;
         }
 
-        if (adb_lseek(package_fd, offset, SEEK_SET) != static_cast<int>(offset)) {
+        if (adb_lseek(package_fd, offset, SEEK_SET) != offset) {
             fprintf(stderr, "adb: failed to seek to package block: %s\n", strerror(errno));
             return -1;
         }
diff --git a/adb/sysdeps.h b/adb/sysdeps.h
index be0bdd0..b8d7e06 100644
--- a/adb/sysdeps.h
+++ b/adb/sysdeps.h
@@ -52,10 +52,11 @@
 #include <fcntl.h>
 #include <io.h>
 #include <process.h>
+#include <stdint.h>
 #include <sys/stat.h>
 #include <utime.h>
-#include <winsock2.h>
 #include <windows.h>
+#include <winsock2.h>
 #include <ws2tcpip.h>
 
 #include <memory>   // unique_ptr
@@ -92,7 +93,7 @@
 extern int adb_creat(const char* path, int mode);
 extern int adb_read(int fd, void* buf, int len);
 extern int adb_write(int fd, const void* buf, int len);
-extern int adb_lseek(int fd, int pos, int where);
+extern int64_t adb_lseek(int fd, int64_t pos, int where);
 extern int adb_shutdown(int fd, int direction = SHUT_RDWR);
 extern int adb_close(int fd);
 extern int adb_register_socket(SOCKET s);
@@ -315,25 +316,24 @@
 
 #else /* !_WIN32 a.k.a. Unix */
 
-#include <cutils/sockets.h>
 #include <fcntl.h>
-#include <poll.h>
-#include <signal.h>
-#include <sys/stat.h>
-#include <sys/wait.h>
-
-#include <pthread.h>
-#include <unistd.h>
-#include <fcntl.h>
-#include <stdarg.h>
 #include <netdb.h>
 #include <netinet/in.h>
 #include <netinet/tcp.h>
+#include <poll.h>
+#include <pthread.h>
+#include <signal.h>
+#include <stdarg.h>
+#include <stdint.h>
 #include <string.h>
+#include <sys/stat.h>
+#include <sys/wait.h>
 #include <unistd.h>
 
 #include <string>
 
+#include <cutils/sockets.h>
+
 #define OS_PATH_SEPARATORS "/"
 #define OS_PATH_SEPARATOR '/'
 #define OS_PATH_SEPARATOR_STR "/"
@@ -443,12 +443,15 @@
 #undef   write
 #define  write  ___xxx_write
 
-static __inline__ int   adb_lseek(int  fd, int  pos, int  where)
-{
+static __inline__ int64_t adb_lseek(int fd, int64_t pos, int where) {
+#if defined(__APPLE__)
     return lseek(fd, pos, where);
+#else
+    return lseek64(fd, pos, where);
+#endif
 }
-#undef   lseek
-#define  lseek   ___xxx_lseek
+#undef lseek
+#define lseek ___xxx_lseek
 
 static __inline__  int    adb_unlink(const char*  path)
 {
diff --git a/adb/sysdeps_win32.cpp b/adb/sysdeps_win32.cpp
index 026dd1c..8784757 100644
--- a/adb/sysdeps_win32.cpp
+++ b/adb/sysdeps_win32.cpp
@@ -52,12 +52,11 @@
 
 typedef const struct FHClassRec_* FHClass;
 typedef struct FHRec_* FH;
-typedef struct EventHookRec_* EventHook;
 
 typedef struct FHClassRec_ {
     void (*_fh_init)(FH);
     int (*_fh_close)(FH);
-    int (*_fh_lseek)(FH, int, int);
+    int64_t (*_fh_lseek)(FH, int64_t, int);
     int (*_fh_read)(FH, void*, int);
     int (*_fh_write)(FH, const void*, int);
     int (*_fh_writev)(FH, const adb_iovec*, int);
@@ -65,7 +64,7 @@
 
 static void _fh_file_init(FH);
 static int _fh_file_close(FH);
-static int _fh_file_lseek(FH, int, int);
+static int64_t _fh_file_lseek(FH, int64_t, int);
 static int _fh_file_read(FH, void*, int);
 static int _fh_file_write(FH, const void*, int);
 static int _fh_file_writev(FH, const adb_iovec*, int);
@@ -81,7 +80,7 @@
 
 static void _fh_socket_init(FH);
 static int _fh_socket_close(FH);
-static int _fh_socket_lseek(FH, int, int);
+static int64_t _fh_socket_lseek(FH, int64_t, int);
 static int _fh_socket_read(FH, void*, int);
 static int _fh_socket_write(FH, const void*, int);
 static int _fh_socket_writev(FH, const adb_iovec*, int);
@@ -318,10 +317,8 @@
     return wrote_bytes;
 }
 
-static int _fh_file_lseek(FH f, int pos, int origin) {
+static int64_t _fh_file_lseek(FH f, int64_t pos, int origin) {
     DWORD method;
-    DWORD result;
-
     switch (origin) {
         case SEEK_SET:
             method = FILE_BEGIN;
@@ -337,14 +334,13 @@
             return -1;
     }
 
-    result = SetFilePointer(f->fh_handle, pos, nullptr, method);
-    if (result == INVALID_SET_FILE_POINTER) {
+    LARGE_INTEGER li = {.QuadPart = pos};
+    if (!SetFilePointerEx(f->fh_handle, li, &li, method)) {
         errno = EIO;
         return -1;
-    } else {
-        f->eof = 0;
     }
-    return (int)result;
+    f->eof = 0;
+    return li.QuadPart;
 }
 
 /**************************************************************************/
@@ -491,14 +487,12 @@
     return f->clazz->_fh_writev(f, iov, iovcnt);
 }
 
-int adb_lseek(int fd, int pos, int where) {
+int64_t adb_lseek(int fd, int64_t pos, int where) {
     FH f = _fh_from_int(fd, __func__);
-
     if (!f) {
         errno = EBADF;
         return -1;
     }
-
     return f->clazz->_fh_lseek(f, pos, where);
 }
 
@@ -644,7 +638,7 @@
     return 0;
 }
 
-static int _fh_socket_lseek(FH f, int pos, int origin) {
+static int64_t _fh_socket_lseek(FH f, int64_t pos, int origin) {
     errno = EPIPE;
     return -1;
 }