diff --git a/applypatch/Android.mk b/applypatch/Android.mk
index 04ddfd8..2cce81f 100644
--- a/applypatch/Android.mk
+++ b/applypatch/Android.mk
@@ -40,7 +40,7 @@
 LOCAL_MODULE := applypatch
 LOCAL_MODULE_TAGS := optional
 LOCAL_C_INCLUDES += $(commands_recovery_local_path)
-LOCAL_STATIC_LIBRARIES += libapplypatch libmtdutils libmincrypttwrp libbz libminelf
+LOCAL_STATIC_LIBRARIES += libapplypatch libmtdutils libmincrypttwrp libbz
 LOCAL_SHARED_LIBRARIES += libz libcutils libstdc++ libc
 
 include $(BUILD_EXECUTABLE)
@@ -50,9 +50,9 @@
 LOCAL_SRC_FILES := main.c
 LOCAL_MODULE := applypatch_static
 LOCAL_FORCE_STATIC_EXECUTABLE := true
-LOCAL_MODULE_TAGS := optional
+LOCAL_MODULE_TAGS := optional eng
 LOCAL_C_INCLUDES += $(commands_recovery_local_path)
-LOCAL_STATIC_LIBRARIES += libapplypatch libmtdutils libmincrypttwrp libbz libminelf
+LOCAL_STATIC_LIBRARIES += libapplypatch libmtdutils libmincrypttwrp libbz
 LOCAL_STATIC_LIBRARIES += libz libcutils libstdc++ libc
 
 include $(BUILD_EXECUTABLE)
diff --git a/applypatch/applypatch.c b/applypatch/applypatch.c
index b5ff12c..73195d9 100644
--- a/applypatch/applypatch.c
+++ b/applypatch/applypatch.c
@@ -24,6 +24,7 @@
 #include <sys/types.h>
 #include <fcntl.h>
 #include <unistd.h>
+#include <stdbool.h>
 
 #include "mincrypt/sha.h"
 #include "applypatch.h"
@@ -32,7 +33,7 @@
 #include "edify/expr.h"
 
 static int LoadPartitionContents(const char* filename, FileContents* file);
-static ssize_t FileSink(unsigned char* data, ssize_t len, void* token);
+static ssize_t FileSink(const unsigned char* data, ssize_t len, void* token);
 static int GenerateTarget(FileContents* source_file,
                           const Value* source_patch_value,
                           FileContents* copy_file,
@@ -45,14 +46,11 @@
 
 static int mtd_partitions_scanned = 0;
 
-// Read a file into memory; optionally (retouch_flag == RETOUCH_DO_MASK) mask
-// the retouched entries back to their original value (such that SHA-1 checks
-// don't fail due to randomization); store the file contents and associated
+// Read a file into memory; store the file contents and associated
 // metadata in *file.
 //
 // Return 0 on success.
-int LoadFileContents(const char* filename, FileContents* file,
-                     int retouch_flag) {
+int LoadFileContents(const char* filename, FileContents* file) {
     file->data = NULL;
 
     // A special 'filename' beginning with "MTD:" or "EMMC:" means to
@@ -89,20 +87,6 @@
     }
     fclose(f);
 
-    // apply_patch[_check] functions are blind to randomization. Randomization
-    // is taken care of in [Undo]RetouchBinariesFn. If there is a mismatch
-    // within a file, this means the file is assumed "corrupt" for simplicity.
-    if (retouch_flag) {
-        int32_t desired_offset = 0;
-        if (retouch_mask_data(file->data, file->size,
-                              &desired_offset, NULL) != RETOUCH_DATA_MATCHED) {
-            printf("error trying to mask retouch entries\n");
-            free(file->data);
-            file->data = NULL;
-            return -1;
-        }
-    }
-
     SHA_hash(file->data, file->size, file->sha1);
     return 0;
 }
@@ -259,7 +243,7 @@
                     break;
             }
             if (next != read) {
-                printf("short read (%d bytes of %d) for partition \"%s\"\n",
+                printf("short read (%zu bytes of %zu) for partition \"%s\"\n",
                        read, next, partition);
                 free(file->data);
                 file->data = NULL;
@@ -286,7 +270,7 @@
         if (memcmp(sha_so_far, parsed_sha, SHA_DIGEST_SIZE) == 0) {
             // we have a match.  stop reading the partition; we'll return
             // the data we've read so far.
-            printf("partition read matched size %d sha %s\n",
+            printf("partition read matched size %zu sha %s\n",
                    size[index[i]], sha1sum[index[i]]);
             break;
         }
@@ -337,7 +321,7 @@
 // Save the contents of the given FileContents object under the given
 // filename.  Return 0 on success.
 int SaveFileContents(const char* filename, const FileContents* file) {
-    int fd = open(filename, O_WRONLY | O_CREAT | O_TRUNC, S_IRUSR | S_IWUSR);
+    int fd = open(filename, O_WRONLY | O_CREAT | O_TRUNC | O_SYNC, S_IRUSR | S_IWUSR);
     if (fd < 0) {
         printf("failed to open \"%s\" for write: %s\n",
                filename, strerror(errno));
@@ -352,8 +336,14 @@
         close(fd);
         return -1;
     }
-    fsync(fd);
-    close(fd);
+    if (fsync(fd) != 0) {
+        printf("fsync of \"%s\" failed: %s\n", filename, strerror(errno));
+        return -1;
+    }
+    if (close(fd) != 0) {
+        printf("close of \"%s\" failed: %s\n", filename, strerror(errno));
+        return -1;
+    }
 
     if (chmod(filename, file->st.st_mode) != 0) {
         printf("chmod of \"%s\" failed: %s\n", filename, strerror(errno));
@@ -433,7 +423,7 @@
 
             size_t written = mtd_write_data(ctx, (char*)data, len);
             if (written != len) {
-                printf("only wrote %d of %d bytes to MTD %s\n",
+                printf("only wrote %zu of %zu bytes to MTD %s\n",
                        written, len, partition);
                 mtd_write_close(ctx);
                 return -1;
@@ -462,13 +452,11 @@
             }
             int attempt;
 
-            for (attempt = 0; attempt < 10; ++attempt) {
-                size_t next_sync = start + (1<<20);
-                printf("raw O_SYNC write %s attempt %d start at %d\n", partition, attempt+1, start);
+            for (attempt = 0; attempt < 2; ++attempt) {
                 lseek(fd, start, SEEK_SET);
                 while (start < len) {
                     size_t to_write = len - start;
-                    if (to_write > 4096) to_write = 4096;
+                    if (to_write > 1<<20) to_write = 1<<20;
 
                     ssize_t written = write(fd, data+start, to_write);
                     if (written < 0) {
@@ -481,12 +469,23 @@
                         }
                     }
                     start += written;
-                    if (start >= next_sync) {
-                        fsync(fd);
-                        next_sync = start + (1<<20);
-                    }
                 }
-                fsync(fd);
+                if (fsync(fd) != 0) {
+                   printf("failed to sync to %s (%s)\n",
+                          partition, strerror(errno));
+                   return -1;
+                }
+                if (close(fd) != 0) {
+                   printf("failed to close %s (%s)\n",
+                          partition, strerror(errno));
+                   return -1;
+                }
+                fd = open(partition, O_RDONLY);
+                if (fd < 0) {
+                   printf("failed to reopen %s for verify (%s)\n",
+                          partition, strerror(errno));
+                   return -1;
+                }
 
                 // drop caches so our subsequent verification read
                 // won't just be reading the cache.
@@ -513,20 +512,20 @@
                             if (errno == EINTR) {
                                 read_count = 0;
                             } else {
-                                printf("verify read error %s at %d: %s\n",
+                                printf("verify read error %s at %zu: %s\n",
                                        partition, p, strerror(errno));
                                 return -1;
                             }
                         }
                         if ((size_t)read_count < to_read) {
-                            printf("short verify read %s at %d: %d %d %s\n",
+                            printf("short verify read %s at %zu: %zd %zu %s\n",
                                    partition, p, read_count, to_read, strerror(errno));
                         }
                         so_far += read_count;
                     }
 
                     if (memcmp(buffer, data+p, to_read)) {
-                        printf("verification failed starting at %d\n", p);
+                        printf("verification failed starting at %zu\n", p);
                         start = p;
                         break;
                     }
@@ -537,8 +536,6 @@
                     success = true;
                     break;
                 }
-
-                sleep(2);
             }
 
             if (!success) {
@@ -550,11 +547,7 @@
                 printf("error closing %s (%s)\n", partition, strerror(errno));
                 return -1;
             }
-            // hack: sync and sleep after closing in hopes of getting
-            // the data actually onto flash.
-            printf("sleeping after close\n");
             sync();
-            sleep(5);
             break;
         }
     }
@@ -622,7 +615,7 @@
     // LoadFileContents is successful.  (Useful for reading
     // partitions, where the filename encodes the sha1s; no need to
     // check them twice.)
-    if (LoadFileContents(filename, &file, RETOUCH_DO_MASK) != 0 ||
+    if (LoadFileContents(filename, &file) != 0 ||
         (num_patches > 0 &&
          FindMatchingPatch(file.sha1, patch_sha1_str, num_patches) < 0)) {
         printf("file \"%s\" doesn't have any of expected "
@@ -637,7 +630,7 @@
         // exists and matches the sha1 we're looking for, the check still
         // passes.
 
-        if (LoadFileContents(CACHE_TEMP_SOURCE, &file, RETOUCH_DO_MASK) != 0) {
+        if (LoadFileContents(CACHE_TEMP_SOURCE, &file) != 0) {
             printf("failed to load cache file\n");
             return 1;
         }
@@ -658,7 +651,7 @@
     return 0;
 }
 
-ssize_t FileSink(unsigned char* data, ssize_t len, void* token) {
+ssize_t FileSink(const unsigned char* data, ssize_t len, void* token) {
     int fd = *(int *)token;
     ssize_t done = 0;
     ssize_t wrote;
@@ -679,7 +672,7 @@
     ssize_t pos;
 } MemorySinkInfo;
 
-ssize_t MemorySink(unsigned char* data, ssize_t len, void* token) {
+ssize_t MemorySink(const unsigned char* data, ssize_t len, void* token) {
     MemorySinkInfo* msi = (MemorySinkInfo*)token;
     if (msi->size - msi->pos < len) {
         return -1;
@@ -773,8 +766,7 @@
     const Value* copy_patch_value = NULL;
 
     // We try to load the target file into the source_file object.
-    if (LoadFileContents(target_filename, &source_file,
-                         RETOUCH_DO_MASK) == 0) {
+    if (LoadFileContents(target_filename, &source_file) == 0) {
         if (memcmp(source_file.sha1, target_sha1, SHA_DIGEST_SIZE) == 0) {
             // The early-exit case:  the patch was already applied, this file
             // has the desired hash, nothing for us to do.
@@ -793,8 +785,7 @@
         // target file, or we did but it's different from the source file.
         free(source_file.data);
         source_file.data = NULL;
-        LoadFileContents(source_filename, &source_file,
-                         RETOUCH_DO_MASK);
+        LoadFileContents(source_filename, &source_file);
     }
 
     if (source_file.data != NULL) {
@@ -810,8 +801,7 @@
         source_file.data = NULL;
         printf("source file is bad; trying copy\n");
 
-        if (LoadFileContents(CACHE_TEMP_SOURCE, &copy_file,
-                             RETOUCH_DO_MASK) < 0) {
+        if (LoadFileContents(CACHE_TEMP_SOURCE, &copy_file) < 0) {
             // fail.
             printf("failed to read copy file\n");
             return 1;
@@ -984,7 +974,8 @@
             strcpy(outname, target_filename);
             strcat(outname, ".patch");
 
-            output = open(outname, O_WRONLY | O_CREAT | O_TRUNC, S_IRUSR | S_IWUSR);
+            output = open(outname, O_WRONLY | O_CREAT | O_TRUNC | O_SYNC,
+                S_IRUSR | S_IWUSR);
             if (output < 0) {
                 printf("failed to open output file %s: %s\n",
                        outname, strerror(errno));
@@ -1015,8 +1006,14 @@
         }
 
         if (output >= 0) {
-            fsync(output);
-            close(output);
+            if (fsync(output) != 0) {
+                printf("failed to fsync file \"%s\" (%s)\n", outname, strerror(errno));
+                result = 1;
+            }
+            if (close(output) != 0) {
+                printf("failed to close file \"%s\" (%s)\n", outname, strerror(errno));
+                result = 1;
+            }
         }
 
         if (result != 0) {
diff --git a/applypatch/applypatch.h b/applypatch/applypatch.h
index f1f13a1..edec848 100644
--- a/applypatch/applypatch.h
+++ b/applypatch/applypatch.h
@@ -19,7 +19,6 @@
 
 #include <sys/stat.h>
 #include "mincrypt/sha.h"
-#include "minelf/Retouch.h"
 #include "edify/expr.h"
 
 typedef struct _Patch {
@@ -41,7 +40,7 @@
 // and use it as the source instead.
 #define CACHE_TEMP_SOURCE "/cache/saved.file"
 
-typedef ssize_t (*SinkFn)(unsigned char*, ssize_t, void*);
+typedef ssize_t (*SinkFn)(const unsigned char*, ssize_t, void*);
 
 // applypatch.c
 int ShowLicenses();
@@ -61,8 +60,7 @@
                      int num_patches,
                      char** const patch_sha1_str);
 
-int LoadFileContents(const char* filename, FileContents* file,
-                     int retouch_flag);
+int LoadFileContents(const char* filename, FileContents* file);
 int SaveFileContents(const char* filename, const FileContents* file);
 void FreeFileContents(FileContents* file);
 int FindMatchingPatch(uint8_t* sha1, char* const * const patch_sha1_str,
diff --git a/applypatch/bspatch.c b/applypatch/bspatch.c
index 2e80f81..b34ec2a 100644
--- a/applypatch/bspatch.c
+++ b/applypatch/bspatch.c
@@ -112,9 +112,7 @@
         printf("short write of output: %d (%s)\n", errno, strerror(errno));
         return 1;
     }
-    if (ctx) {
-        SHA_update(ctx, new_data, new_size);
-    }
+    if (ctx) SHA_update(ctx, new_data, new_size);
     free(new_data);
 
     return 0;
@@ -205,6 +203,11 @@
         ctrl[1] = offtin(buf+8);
         ctrl[2] = offtin(buf+16);
 
+        if (ctrl[0] < 0 || ctrl[1] < 0) {
+            printf("corrupt patch (negative byte counts)\n");
+            return 1;
+        }
+
         // Sanity check
         if (newpos + ctrl[0] > *new_size) {
             printf("corrupt patch (new file overrun)\n");
diff --git a/applypatch/imgpatch.c b/applypatch/imgpatch.c
index 3a1df38..33c4487 100644
--- a/applypatch/imgpatch.c
+++ b/applypatch/imgpatch.c
@@ -18,6 +18,7 @@
 // format.
 
 #include <stdio.h>
+#include <sys/cdefs.h>
 #include <sys/stat.h>
 #include <errno.h>
 #include <unistd.h>
@@ -35,7 +36,7 @@
  * file, and update the SHA context with the output data as well.
  * Return 0 on success.
  */
-int ApplyImagePatch(const unsigned char* old_data, ssize_t old_size,
+int ApplyImagePatch(const unsigned char* old_data, ssize_t old_size __unused,
                     const Value* patch,
                     SinkFn sink, void* token, SHA_CTX* ctx,
                     const Value* bonus_data) {
@@ -94,7 +95,7 @@
                 printf("failed to read chunk %d raw data\n", i);
                 return -1;
             }
-            SHA_update(ctx, patch->data + pos, data_len);
+            if (ctx) SHA_update(ctx, patch->data + pos, data_len);
             if (sink((unsigned char*)patch->data + pos,
                      data_len, token) != data_len) {
                 printf("failed to write chunk %d raw data\n", i);
@@ -132,7 +133,7 @@
 
             unsigned char* expanded_source = malloc(expanded_len);
             if (expanded_source == NULL) {
-                printf("failed to allocate %d bytes for expanded_source\n",
+                printf("failed to allocate %zu bytes for expanded_source\n",
                        expanded_len);
                 return -1;
             }
@@ -163,7 +164,7 @@
             // We should have filled the output buffer exactly, except
             // for the bonus_size.
             if (strm.avail_out != bonus_size) {
-                printf("source inflation short by %d bytes\n", strm.avail_out-bonus_size);
+                printf("source inflation short by %zu bytes\n", strm.avail_out-bonus_size);
                 return -1;
             }
             inflateEnd(&strm);
@@ -216,7 +217,7 @@
                            (long)have);
                     return -1;
                 }
-                SHA_update(ctx, temp_data, have);
+                if (ctx) SHA_update(ctx, temp_data, have);
             } while (ret != Z_STREAM_END);
             deflateEnd(&strm);
 
diff --git a/applypatch/main.c b/applypatch/main.c
index f61db5d..8e9fe80 100644
--- a/applypatch/main.c
+++ b/applypatch/main.c
@@ -74,7 +74,7 @@
             (*patches)[i] = NULL;
         } else {
             FileContents fc;
-            if (LoadFileContents(colon, &fc, RETOUCH_DONT_MASK) != 0) {
+            if (LoadFileContents(colon, &fc) != 0) {
                 goto abort;
             }
             (*patches)[i] = malloc(sizeof(Value));
@@ -103,7 +103,7 @@
     Value* bonus = NULL;
     if (argc >= 3 && strcmp(argv[1], "-b") == 0) {
         FileContents fc;
-        if (LoadFileContents(argv[2], &fc, RETOUCH_DONT_MASK) != 0) {
+        if (LoadFileContents(argv[2], &fc) != 0) {
             printf("failed to load bonus file %s\n", argv[2]);
             return 1;
         }