diff --git a/common.h b/common.h
index 29b37bb..0c250f4 100644
--- a/common.h
+++ b/common.h
@@ -73,12 +73,12 @@ void ui_show_indeterminate_progress();
 void ui_reset_progress();
 
 #define LOGE(...) ui_print("E:" __VA_ARGS__)
-#define LOGW(...) fprintf(stderr, "W:" __VA_ARGS__)
-#define LOGI(...) fprintf(stderr, "I:" __VA_ARGS__)
+#define LOGW(...) fprintf(stdout, "W:" __VA_ARGS__)
+#define LOGI(...) fprintf(stdout, "I:" __VA_ARGS__)
 
 #if 0
-#define LOGV(...) fprintf(stderr, "V:" __VA_ARGS__)
-#define LOGD(...) fprintf(stderr, "D:" __VA_ARGS__)
+#define LOGV(...) fprintf(stdout, "V:" __VA_ARGS__)
+#define LOGD(...) fprintf(stdout, "D:" __VA_ARGS__)
 #else
 #define LOGV(...) do {} while (0)
 #define LOGD(...) do {} while (0)
diff --git a/install.c b/install.c
index 40f182d..2619a0c 100644
--- a/install.c
+++ b/install.c
@@ -112,7 +112,7 @@ try_update_binary(const char *path, ZipArchive *zip) {
     if (pid == 0) {
         close(pipefd[0]);
         execv(binary, args);
-        fprintf(stderr, "E:Can't run %s (%s)\n", binary, strerror(errno));
+        fprintf(stdout, "E:Can't run %s (%s)\n", binary, strerror(errno));
         _exit(-1);
     }
     close(pipefd[1]);
diff --git a/recovery.c b/recovery.c
index 30bbe38..286f1e5 100644
--- a/recovery.c
+++ b/recovery.c
@@ -673,7 +673,7 @@ prompt_and_wait() {
 
 static void
 print_property(const char *key, const char *name, void *cookie) {
-    fprintf(stderr, "%s=%s\n", key, name);
+    printf("%s=%s\n", key, name);
 }
 
 int
@@ -683,7 +683,7 @@ main(int argc, char **argv) {
     // If these fail, there's not really anywhere to complain...
     freopen(TEMPORARY_LOG_FILE, "a", stdout); setbuf(stdout, NULL);
     freopen(TEMPORARY_LOG_FILE, "a", stderr); setbuf(stderr, NULL);
-    fprintf(stderr, "Starting recovery on %s", ctime(&start));
+    printf("Starting recovery on %s", ctime(&start));
 
     ui_init();
     get_args(&argc, &argv);
@@ -714,14 +714,14 @@ main(int argc, char **argv) {
 
     device_recovery_start();
 
-    fprintf(stderr, "Command:");
+    printf("Command:");
     for (arg = 0; arg < argc; arg++) {
-        fprintf(stderr, " \"%s\"", argv[arg]);
+        printf(" \"%s\"", argv[arg]);
     }
-    fprintf(stderr, "\n\n");
+    printf("\n\n");
 
     property_list(print_property, NULL);
-    fprintf(stderr, "\n");
+    printf("\n");
 
     int status = INSTALL_SUCCESS;
 
diff --git a/ui.c b/ui.c
index 01c37c0..13df169 100644
--- a/ui.c
+++ b/ui.c
@@ -404,7 +404,7 @@ void ui_print(const char *fmt, ...)
     vsnprintf(buf, 256, fmt, ap);
     va_end(ap);
 
-    fputs(buf, stderr);
+    fputs(buf, stdout);
 
     // This can get called before ui_init(), so be careful.
     pthread_mutex_lock(&gUpdateMutex);
diff --git a/updater/Android.mk b/updater/Android.mk
index d4a4e33..dcc6a49 100644
--- a/updater/Android.mk
+++ b/updater/Android.mk
@@ -18,7 +18,13 @@ LOCAL_MODULE_TAGS := eng
 
 LOCAL_SRC_FILES := $(updater_src_files)
 
-LOCAL_STATIC_LIBRARIES := $(TARGET_RECOVERY_UPDATER_LIBS) $(TARGET_RECOVERY_UPDATER_EXTRA_LIBS)
+ifeq ($(TARGET_USERIMAGES_USE_EXT4), true)
+LOCAL_CFLAGS += -DUSE_EXT4
+LOCAL_C_INCLUDES += system/extras/ext4_utils
+LOCAL_STATIC_LIBRARIES += libext4_utils libz
+endif
+
+LOCAL_STATIC_LIBRARIES += $(TARGET_RECOVERY_UPDATER_LIBS) $(TARGET_RECOVERY_UPDATER_EXTRA_LIBS)
 LOCAL_STATIC_LIBRARIES += libapplypatch libedify libmtdutils libminzip libz
 LOCAL_STATIC_LIBRARIES += libmincrypt libbz
 LOCAL_STATIC_LIBRARIES += libcutils libstdc++ libc
diff --git a/updater/install.c b/updater/install.c
index e869134..167b402 100644
--- a/updater/install.c
+++ b/updater/install.c
@@ -36,24 +36,35 @@
 #include "updater.h"
 #include "applypatch/applypatch.h"
 
-// mount(type, location, mount_point)
+#ifdef USE_EXT4
+#include "make_ext4fs.h"
+#endif
+
+// mount(fs_type, partition_type, location, mount_point)
 //
-//   what:  type="MTD"   location="<partition>"            to mount a yaffs2 filesystem
-//          type="vfat"  location="/dev/block/<whatever>"  to mount a device
+//    fs_type="yaffs2" partition_type="MTD"     location=partition
+//    fs_type="ext4"   partition_type="EMMC"    location=device
 Value* MountFn(const char* name, State* state, int argc, Expr* argv[]) {
     char* result = NULL;
-    if (argc != 3) {
-        return ErrorAbort(state, "%s() expects 3 args, got %d", name, argc);
+    if (argc != 4) {
+        return ErrorAbort(state, "%s() expects 4 args, got %d", name, argc);
     }
-    char* type;
+    char* fs_type;
+    char* partition_type;
     char* location;
     char* mount_point;
-    if (ReadArgs(state, argv, 3, &type, &location, &mount_point) < 0) {
+    if (ReadArgs(state, argv, 4, &fs_type, &partition_type,
+                 &location, &mount_point) < 0) {
         return NULL;
     }
 
-    if (strlen(type) == 0) {
-        ErrorAbort(state, "type argument to %s() can't be empty", name);
+    if (strlen(fs_type) == 0) {
+        ErrorAbort(state, "fs_type argument to %s() can't be empty", name);
+        goto done;
+    }
+    if (strlen(partition_type) == 0) {
+        ErrorAbort(state, "partition_type argument to %s() can't be empty",
+                   name);
         goto done;
     }
     if (strlen(location) == 0) {
@@ -67,7 +78,7 @@ Value* MountFn(const char* name, State* state, int argc, Expr* argv[]) {
 
     mkdir(mount_point, 0755);
 
-    if (strcmp(type, "MTD") == 0) {
+    if (strcmp(partition_type, "MTD") == 0) {
         mtd_scan_partitions();
         const MtdPartition* mtd;
         mtd = mtd_find_partition_by_name(location);
@@ -77,7 +88,7 @@ Value* MountFn(const char* name, State* state, int argc, Expr* argv[]) {
             result = strdup("");
             goto done;
         }
-        if (mtd_mount_partition(mtd, mount_point, "yaffs2", 0 /* rw */) != 0) {
+        if (mtd_mount_partition(mtd, mount_point, fs_type, 0 /* rw */) != 0) {
             fprintf(stderr, "mtd mount of %s failed: %s\n",
                     location, strerror(errno));
             result = strdup("");
@@ -85,7 +96,7 @@ Value* MountFn(const char* name, State* state, int argc, Expr* argv[]) {
         }
         result = mount_point;
     } else {
-        if (mount(location, mount_point, type,
+        if (mount(location, mount_point, fs_type,
                   MS_NOATIME | MS_NODEV | MS_NODIRATIME, "") < 0) {
             fprintf(stderr, "%s: failed to mount %s at %s: %s\n",
                     name, location, mount_point, strerror(errno));
@@ -96,7 +107,8 @@ Value* MountFn(const char* name, State* state, int argc, Expr* argv[]) {
     }
 
 done:
-    free(type);
+    free(fs_type);
+    free(partition_type);
     free(location);
     if (result != mount_point) free(mount_point);
     return StringValue(result);
@@ -162,22 +174,29 @@ done:
 }
 
 
-// format(type, location)
+// format(fs_type, partition_type, location)
 //
-//    type="MTD"  location=partition
+//    fs_type="yaffs2" partition_type="MTD"     location=partition
+//    fs_type="ext4"   partition_type="EMMC"    location=device
 Value* FormatFn(const char* name, State* state, int argc, Expr* argv[]) {
     char* result = NULL;
-    if (argc != 2) {
-        return ErrorAbort(state, "%s() expects 2 args, got %d", name, argc);
+    if (argc != 3) {
+        return ErrorAbort(state, "%s() expects 3 args, got %d", name, argc);
     }
-    char* type;
+    char* fs_type;
+    char* partition_type;
     char* location;
-    if (ReadArgs(state, argv, 2, &type, &location) < 0) {
+    if (ReadArgs(state, argv, 3, &fs_type, &partition_type, &location) < 0) {
         return NULL;
     }
 
-    if (strlen(type) == 0) {
-        ErrorAbort(state, "type argument to %s() can't be empty", name);
+    if (strlen(fs_type) == 0) {
+        ErrorAbort(state, "fs_type argument to %s() can't be empty", name);
+        goto done;
+    }
+    if (strlen(partition_type) == 0) {
+        ErrorAbort(state, "partition_type argument to %s() can't be empty",
+                   name);
         goto done;
     }
     if (strlen(location) == 0) {
@@ -185,7 +204,7 @@ Value* FormatFn(const char* name, State* state, int argc, Expr* argv[]) {
         goto done;
     }
 
-    if (strcmp(type, "MTD") == 0) {
+    if (strcmp(partition_type, "MTD") == 0) {
         mtd_scan_partitions();
         const MtdPartition* mtd = mtd_find_partition_by_name(location);
         if (mtd == NULL) {
@@ -212,12 +231,26 @@ Value* FormatFn(const char* name, State* state, int argc, Expr* argv[]) {
             goto done;
         }
         result = location;
+#ifdef USE_EXT4
+    } else if (strcmp(fs_type, "ext4") == 0) {
+        reset_ext4fs_info();
+        int status = make_ext4fs(location, NULL, NULL, 0, 0);
+        if (status != 0) {
+            fprintf(stderr, "%s: make_ext4fs failed (%d) on %s",
+                    name, status, location);
+            result = strdup("");
+            goto done;
+        }
+        result = location;
+#endif
     } else {
-        fprintf(stderr, "%s: unsupported type \"%s\"", name, type);
+        fprintf(stderr, "%s: unsupported fs_type \"%s\" partition_type \"%s\"",
+                name, fs_type, partition_type);
     }
 
 done:
-    free(type);
+    free(fs_type);
+    free(partition_type);
     if (result != location) free(location);
     return StringValue(result);
 }