diff --git a/native/jni/core/bootstages.c b/native/jni/core/bootstages.c
index 7a74c4cf9..bd0ad3838 100644
--- a/native/jni/core/bootstages.c
+++ b/native/jni/core/bootstages.c
@@ -441,17 +441,10 @@ static int prepare_img() {
 			vec_push_back(&module_list, strdup(entry->d_name));
 		}
 	}
-
 	closedir(dir);
 
-	// Trim image
-	umount_image(MOUNTPOINT, magiskloop);
-	free(magiskloop);
-	trim_img(MAINIMG);
-
-	// Remount them back :)
-	magiskloop = mount_image(MAINIMG, MOUNTPOINT);
-	free(magiskloop);
+	if (trim_img(MAINIMG, MOUNTPOINT, magiskloop))
+		return 1;
 	return 0;
 }
 
diff --git a/native/jni/core/magisk.c b/native/jni/core/magisk.c
index cc0470967..926f3b32f 100644
--- a/native/jni/core/magisk.c
+++ b/native/jni/core/magisk.c
@@ -12,7 +12,8 @@
 
 char *argv0;
 
-int (*applet_main[]) (int, char *[]) = { su_client_main, resetprop_main, magiskhide_main, NULL };
+int (*applet_main[]) (int, char *[]) =
+		{ su_client_main, resetprop_main, magiskhide_main, imgtool_main, NULL };
 
 int create_links(const char *bin, const char *path) {
 	char self[PATH_MAX], linkpath[PATH_MAX];
@@ -42,11 +43,6 @@ static void usage() {
 		"   -V                        print running daemon version code\n"
 		"   --list                    list all available applets\n"
 		"   --install [SOURCE] DIR    symlink all applets to DIR. SOURCE is optional\n"
-		"   --createimg IMG SIZE      create ext4 image. SIZE is interpreted in MB\n"
-		"   --imgsize IMG             report ext4 image used/total size\n"
-		"   --resizeimg IMG SIZE      resize ext4 image. SIZE is interpreted in MB\n"
-		"   --mountimg IMG PATH       mount IMG to PATH and prints the loop device\n"
-		"   --umountimg PATH LOOP     unmount PATH and delete LOOP device\n"
 		"   --daemon                  manually start magisk daemon\n"
 		"   --[init trigger]          start service for init trigger\n"
 		"   --unlock-blocks           set BLKROSET flag to OFF for all block devices\n"
@@ -90,48 +86,6 @@ int magisk_main(int argc, char *argv[]) {
 		for (int i = 0; applet[i]; ++i)
 			printf("%s\n", applet[i]);
 		return 0;
-	} else if (strcmp(argv[1], "--createimg") == 0) {
-		if (argc < 4) usage();
-		int size;
-		sscanf(argv[3], "%d", &size);
-		return create_img(argv[2], size);
-	} else if (strcmp(argv[1], "--imgsize") == 0) {
-		if (argc < 3) usage();
-		int used, total;
-		if (get_img_size(argv[2], &used, &total)) {
-			fprintf(stderr, "Cannot check %s size\n", argv[2]);
-			return 1;
-		}
-		printf("%d %d\n", used, total);
-		return 0;
-	} else if (strcmp(argv[1], "--resizeimg") == 0) {
-		if (argc < 4) usage();
-		int used, total, size;
-		sscanf(argv[3], "%d", &size);
-		if (get_img_size(argv[2], &used, &total)) {
-			fprintf(stderr, "Cannot check %s size\n", argv[2]);
-			return 1;
-		}
-		if (size <= used) {
-			fprintf(stderr, "Cannot resize smaller than %dM\n", used);
-			return 1;
-		}
-		return resize_img(argv[2], size);
-	} else if (strcmp(argv[1], "--mountimg") == 0) {
-		if (argc < 4) usage();
-		char *loop = mount_image(argv[2], argv[3]);
-		if (loop == NULL) {
-			fprintf(stderr, "Cannot mount image!\n");
-			return 1;
-		} else {
-			printf("%s\n", loop);
-			free(loop);
-			return 0;
-		}
-	} else if (strcmp(argv[1], "--umountimg") == 0) {
-		if (argc < 4) usage();
-		umount_image(argv[2], argv[3]);
-		return 0;
 	} else if (strcmp(argv[1], "--unlock-blocks") == 0) {
 		unlock_blocks();
 		return 0;
diff --git a/native/jni/include/magisk.h b/native/jni/include/magisk.h
index 7607858e5..15356746f 100644
--- a/native/jni/include/magisk.h
+++ b/native/jni/include/magisk.h
@@ -54,7 +54,7 @@
 
 extern char *argv0;     /* For changing process name */
 
-#define applet          ((char *[]) { "su", "resetprop", "magiskhide", NULL })
+#define applet          ((char *[]) { "su", "resetprop", "magiskhide", "imgtool", NULL })
 #define init_applet     ((char *[]) { "magiskpolicy", "supolicy", NULL })
 
 extern int (*applet_main[]) (int, char *[]), (*init_applet_main[]) (int, char *[]);
@@ -66,5 +66,6 @@ int magiskhide_main(int argc, char *argv[]);
 int magiskpolicy_main(int argc, char *argv[]);
 int su_client_main(int argc, char *argv[]);
 int resetprop_main(int argc, char *argv[]);
+int imgtool_main(int argc, char *argv[]);
 
 #endif
diff --git a/native/jni/include/utils.h b/native/jni/include/utils.h
index 8a2c86285..c43242b15 100644
--- a/native/jni/include/utils.h
+++ b/native/jni/include/utils.h
@@ -134,16 +134,15 @@ void write_zero(int fd, size_t size);
 // img.c
 
 #define round_size(a) ((((a) / 32) + 2) * 32)
-#define SOURCE_TMP "/dev/source"
-#define TARGET_TMP "/dev/target"
+#define SOURCE_TMP "/dev/.img_src"
+#define TARGET_TMP "/dev/.img_tgt"
 
 int create_img(const char *img, int size);
-int get_img_size(const char *img, int *used, int *total);
-int resize_img(const char *img, int size);
+int resize_img(const char *img, int size, int enforce);
 char *mount_image(const char *img, const char *target);
-void umount_image(const char *target, const char *device);
+int umount_image(const char *target, const char *device);
 int merge_img(const char *source, const char *target);
-void trim_img(const char *img);
+int trim_img(const char *img, const char *mount, char *loop);
 
 // pattern.c
 
diff --git a/native/jni/utils/img.c b/native/jni/utils/img.c
index 418dd91d7..0c69bed51 100644
--- a/native/jni/utils/img.c
+++ b/native/jni/utils/img.c
@@ -8,11 +8,18 @@
 #include <sys/wait.h>
 #include <sys/mount.h>
 #include <sys/sendfile.h>
+#include <sys/statvfs.h>
 #include <linux/loop.h>
 
 #include "magisk.h"
 #include "utils.h"
 
+struct fs_info {
+	unsigned size;
+	unsigned free;
+	unsigned used;
+};
+
 static int e2fsck(const char *img) {
 	// Check and repair ext4 image
 	char buffer[128];
@@ -51,59 +58,86 @@ static char *loopsetup(const char *img) {
 	return strdup(device);
 }
 
+static void check_filesystem(struct fs_info *info, const char *img, const char *mount) {
+	struct stat st;
+	struct statvfs vfs;
+	stat(img, &st);
+	statvfs(mount, &vfs);
+	info->size = st.st_size / 1048576;
+	info->free = vfs.f_bfree * vfs.f_frsize / 1048576;
+	info->used = (vfs.f_blocks - vfs.f_bfree) * vfs.f_frsize / 1048576;
+}
+
+static void usage() {
+	fprintf(stderr,
+			"ImgTool v" xstr(MAGISK_VERSION) "(" xstr(MAGISK_VER_CODE) ") (by topjohnwu) - EXT4 Image Tools\n"
+			"\n"
+			"Usage: imgtool <action> [args...]\n"
+			"\n"
+			"Actions:\n"
+			"   create IMG SIZE      create ext4 image. SIZE is interpreted in MB\n"
+			"   resize IMG SIZE      resize ext4 image. SIZE is interpreted in MB\n"
+			"   mount  IMG PATH      mount IMG to PATH and prints the loop device\n"
+			"   umount PATH LOOP     unmount PATH and delete LOOP device\n"
+	);
+	exit(1);
+}
+
+int imgtool_main(int argc, char *argv[]) {
+	if (argc < 2)
+		usage();
+	if (strcmp(argv[1], "create") == 0) {
+		if (argc < 4)
+			usage();
+		return create_img(argv[2], atoi(argv[3]));
+	} else if (strcmp(argv[1], "resize") == 0) {
+		if (argc < 4)
+			usage();
+		return resize_img(argv[2], atoi(argv[3]), 1);
+	} else if (strcmp(argv[1], "mount") == 0) {
+		if (argc < 4)
+			usage();
+		char *loop = mount_image(argv[2], argv[3]);
+		if (loop == NULL) {
+			fprintf(stderr, "Cannot mount image!\n");
+			return 1;
+		} else {
+			printf("%s\n", loop);
+			free(loop);
+			return 0;
+		}
+	} else if (strcmp(argv[1], "umount") == 0) {
+		if (argc < 4)
+			usage();
+		umount_image(argv[2], argv[3]);
+		return 0;
+	}
+	usage();
+	return 1;
+}
+
 int create_img(const char *img, int size) {
 	if (size == 128)  /* WTF...? */
 		size = 132;
 	unlink(img);
 	LOGI("Create %s with size %dM\n", img, size);
-	int ret;
-
 	char size_str[16];
 	snprintf(size_str, sizeof(size_str), "%dM", size);
-	ret = exec_command_sync("/system/bin/make_ext4fs", "-b", "4096", "-l", size_str, img, NULL);
-	if (ret < 0) {
+	if (access("/system/bin/make_ext4fs", X_OK) == 0)
+		return exec_command_sync("/system/bin/make_ext4fs", "-b", "4096", "-l", size_str, img, NULL);
+	else if (access("/system/bin/mke2fs", X_OK) == 0)
 		// On Android P there is no make_ext4fs, use mke2fs
-		ret = exec_command_sync("/system/bin/mke2fs", "-b", "4096", "-t", "ext4", img, size_str, NULL);
-	}
-	return ret;
+		return exec_command_sync("/system/bin/mke2fs", "-b", "4096", "-t", "ext4", img, size_str, NULL);
+	else
+		return 1;
 }
 
-int get_img_size(const char *img, int *used, int *total) {
-	if (access(img, R_OK) == -1)
-		return 1;
-	char buffer[PATH_MAX];
-	int pid, fd = -1, status = 1;
-	pid = exec_command(1, &fd, NULL, "/system/bin/e2fsck", "-n", img, NULL);
-	if (pid < 0)
-		return 1;
-	while (fdgets(buffer, sizeof(buffer), fd)) {
-		if (strstr(buffer, img)) {
-			char *tok = strtok(buffer, ",");
-			while(tok != NULL) {
-				if (strstr(tok, "blocks")) {
-					status = 0;
-					break;
-				}
-				tok = strtok(NULL, ",");
-			}
-			if (status) continue;
-			sscanf(tok, "%d/%d", used, total);
-			*used = (*used + 255) / 256;
-			*total = (*total + 128) / 256;
-			break;
-		}
-	}
-	close(fd);
-	waitpid(pid, NULL, 0);
-	return 0;
-}
-
-int resize_img(const char *img, int size) {
+int resize_img(const char *img, int size, int enforce) {
 	LOGI("Resize %s to %dM\n", img, size);
 	if (e2fsck(img))
 		return 1;
 	char buffer[128];
-	int pid, fd = -1, used, total;
+	int pid, fd = -1;
 	snprintf(buffer, sizeof(buffer), "%dM", size);
 	pid = exec_command(1, &fd, NULL, "/system/bin/resize2fs", img, buffer, NULL);
 	if (pid < 0)
@@ -113,29 +147,32 @@ int resize_img(const char *img, int size) {
 	close(fd);
 	waitpid(pid, NULL, 0);
 
-	// Double check our image size
-	get_img_size(img, &used, &total);
-	if (total != size) {
-		// Sammy crap occurs or resize2fs failed, lets create a new image!
-		char *dir = dirname(img);
-		snprintf(buffer, sizeof(buffer), "%s/tmp.img", dir);
-		create_img(buffer, size);
-		char *s_loop, *t_loop;
-		s_loop = mount_image(img, SOURCE_TMP);
-		if (s_loop == NULL) return 1;
-		t_loop = mount_image(buffer, TARGET_TMP);
-		if (t_loop == NULL) return 1;
+	if (enforce) {
+		// Check the image size
+		struct stat st;
+		stat(img, &st);
+		if (st.st_size / 1048576 != size) {
+			// Sammy crap occurs or resize2fs failed, lets create a new image!
+			snprintf(buffer, sizeof(buffer), "%s/tmp.img", dirname(img));
+			create_img(buffer, size);
+			char *s_loop, *t_loop;
+			s_loop = mount_image(img, SOURCE_TMP);
+			if (s_loop == NULL)
+				return 1;
+			t_loop = mount_image(buffer, TARGET_TMP);
+			if (t_loop == NULL)
+				return 1;
 
-		cp_afc(SOURCE_TMP, TARGET_TMP);
-		umount_image(SOURCE_TMP, s_loop);
-		umount_image(TARGET_TMP, t_loop);
-		rmdir(SOURCE_TMP);
-		rmdir(TARGET_TMP);
-		free(s_loop);
-		free(t_loop);
-		rename(buffer, img);
+			cp_afc(SOURCE_TMP, TARGET_TMP);
+			umount_image(SOURCE_TMP, s_loop);
+			umount_image(TARGET_TMP, t_loop);
+			rmdir(SOURCE_TMP);
+			rmdir(TARGET_TMP);
+			free(s_loop);
+			free(t_loop);
+			rename(buffer, img);
+		}
 	}
-
 	return 0;
 }
 
@@ -152,11 +189,13 @@ char *mount_image(const char *img, const char *target) {
 	return device;
 }
 
-void umount_image(const char *target, const char *device) {
-	xumount(target);
+int umount_image(const char *target, const char *device) {
+	int ret = 0;
+	ret |= xumount(target);
 	int fd = xopen(device, O_RDWR);
-	ioctl(fd, LOOP_CLR_FD);
+	ret |= ioctl(fd, LOOP_CLR_FD);
 	close(fd);
+	return ret;
 }
 
 int merge_img(const char *source, const char *target) {
@@ -178,22 +217,30 @@ int merge_img(const char *source, const char *target) {
 
 	char buffer[PATH_MAX];
 
-	// resize target to worst case
-	int s_used, s_total, t_used, t_total, n_total;
-	get_img_size(source, &s_used, &s_total);
-	get_img_size(target, &t_used, &t_total);
-	n_total = round_size(s_used + t_used);
-	if (n_total > t_total)
-		resize_img(target, n_total);
-
 	xmkdir(SOURCE_TMP, 0755);
 	xmkdir(TARGET_TMP, 0755);
 	char *s_loop, *t_loop;
 	s_loop = mount_image(source, SOURCE_TMP);
-	if (s_loop == NULL) return 1;
+	if (s_loop == NULL)
+		return 1;
 	t_loop = mount_image(target, TARGET_TMP);
-	if (t_loop == NULL) return 1;
+	if (t_loop == NULL)
+		return 1;
 
+	struct fs_info src, tgt;
+	check_filesystem(&src, source, SOURCE_TMP);
+	check_filesystem(&tgt, target, TARGET_TMP);
+
+	// resize target to worst case
+	if (src.used >= tgt.free) {
+		umount_image(TARGET_TMP, t_loop);
+		free(t_loop);
+		resize_img(target, round_size(tgt.size + src.used - tgt.free), 1);
+		t_loop = mount_image(target, TARGET_TMP);
+	}
+
+	snprintf(buffer, sizeof(buffer), "%s/%s", TARGET_TMP, "lost+found");
+	rm_rf(buffer);
 	DIR *dir;
 	struct dirent *entry;
 	if (!(dir = xopendir(SOURCE_TMP)))
@@ -207,12 +254,9 @@ int merge_img(const char *source, const char *target) {
 				continue;
 			// Cleanup old module if exists
 			snprintf(buffer, sizeof(buffer), "%s/%s", TARGET_TMP, entry->d_name);
-			if (access(buffer, F_OK) == 0) {
-				LOGI("Upgrade module: %s\n", entry->d_name);
+			if (access(buffer, F_OK) == 0)
 				rm_rf(buffer);
-			} else {
-				LOGI("New module: %s\n", entry->d_name);
-			}
+			LOGI("Upgrade/New module: %s\n", entry->d_name);
 		}
 	}
 	closedir(dir);
@@ -229,10 +273,18 @@ int merge_img(const char *source, const char *target) {
 	return 0;
 }
 
-void trim_img(const char *img) {
-	int used, total, new_size;
-	get_img_size(img, &used, &total);
-	new_size = round_size(used);
-	if (new_size != total)
-		resize_img(img, new_size);
+int trim_img(const char *img, const char *mount, char *loop) {
+	struct fs_info info;
+	check_filesystem(&info, img, mount);
+	int new_size = round_size(info.used);
+	if (info.size > new_size) {
+		umount_image(mount, loop);
+		free(loop);
+		resize_img(img, new_size, 0);
+		loop = mount_image(img, mount);
+		if (loop == NULL)
+			return 1;
+	}
+	free(loop);
+	return 0;
 }
diff --git a/scripts/util_functions.sh b/scripts/util_functions.sh
index 276f88e76..d0d739572 100644
--- a/scripts/util_functions.sh
+++ b/scripts/util_functions.sh
@@ -375,52 +375,55 @@ mktouch() {
 }
 
 request_size_check() {
-  reqSizeM=`du -s $1 | cut -f1`
-  reqSizeM=$((reqSizeM / 1024 + 1))
+  reqSizeM=`du -ms $1 | cut -f1`
 }
 
 request_zip_size_check() {
-  reqSizeM=`unzip -l "$1" | tail -n 1 | awk '{ print int($1 / 1048567 + 1) }'`
+  reqSizeM=`unzip -l "$1" | tail -n 1 | awk '{ print int(($1 - 1) / 1048576 + 1) }'`
 }
 
-image_size_check() {
-  SIZE="`$MAGISKBIN/magisk --imgsize $IMG`"
-  curUsedM=`echo "$SIZE" | cut -d" " -f1`
-  curSizeM=`echo "$SIZE" | cut -d" " -f2`
-  curFreeM=$((curSizeM - curUsedM))
+check_filesystem() {
+  curSizeM=`wc -c < $1`
+  curSizeM=$((curSizeM / 1048576))
+  local DF=`df -P $2 | grep $2`
+  curUsedM=`echo $DF | awk '{ print int($3 / 1024) }'`
+  curFreeM=`echo $DF | awk '{ print int($4 / 1024) }'`
+}
+
+mount_snippet() {
+  MAGISKLOOP=`$MAGISKBIN/magisk imgtool mount $IMG $MOUNTPATH`
+  is_mounted $MOUNTPATH || abort "! $IMG mount failed..."
 }
 
 mount_magisk_img() {
   [ -z reqSizeM ] && reqSizeM=0
+  mkdir -p $MOUNTPATH 2>/dev/null
   if [ -f "$IMG" ]; then
     ui_print "- Found $IMG"
-    image_size_check $IMG
-    if [ "$reqSizeM" -gt "$curFreeM" ]; then
-      newSizeM=$(((reqSizeM + curUsedM) / 32 * 32 + 64))
+    mount_snippet
+    check_filesystem $IMG $MOUNTPATH
+    if [ $reqSizeM -gt $curFreeM ]; then
+      newSizeM=$(((curSizeM + reqSizeM - curFreeM) / 32 * 32 + 64))
       ui_print "- Resizing $IMG to ${newSizeM}M"
-      $MAGISKBIN/magisk --resizeimg $IMG $newSizeM >&2
+      $MAGISKBIN/magisk imgtool umount $MOUNTPATH $MAGISKLOOP
+      $MAGISKBIN/magisk imgtool resize $IMG $newSizeM >&2
+      mount_snippet
     fi
+    ui_print "- Mount $IMG to $MOUNTPATH"
   else
-    newSizeM=$((reqSizeM / 32 * 32 + 64));
+    newSizeM=$((reqSizeM / 32 * 32 + 64))
     ui_print "- Creating $IMG with size ${newSizeM}M"
-    $MAGISKBIN/magisk --createimg $IMG $newSizeM >&2
+    $MAGISKBIN/magisk imgtool create $IMG $newSizeM >&2
+    mount_snippet
   fi
-
-  ui_print "- Mounting $IMG to $MOUNTPATH"
-  mkdir -p $MOUNTPATH 2>/dev/null
-  MAGISKLOOP=`$MAGISKBIN/magisk --mountimg $IMG $MOUNTPATH`
-  is_mounted $MOUNTPATH || abort "! $IMG mount failed..."
 }
 
 unmount_magisk_img() {
-  $MAGISKBIN/magisk --umountimg $MOUNTPATH $MAGISKLOOP
-
-  # Shrink the image if possible
-  image_size_check $IMG
+  check_filesystem $IMG $MOUNTPATH
   newSizeM=$((curUsedM / 32 * 32 + 64))
+  $MAGISKBIN/magisk imgtool umount $MOUNTPATH $MAGISKLOOP
   if [ $curSizeM -gt $newSizeM ]; then
     ui_print "- Shrinking $IMG to ${newSizeM}M"
-    $MAGISKBIN/magisk --resizeimg $IMG $newSizeM
+    $MAGISKBIN/magisk imgtool resize $IMG $newSizeM >&2
   fi
 }
-