Index: sys/geom/label/g_label_ufs.c
===================================================================
--- sys/geom/label/g_label_ufs.c
+++ sys/geom/label/g_label_ufs.c
@@ -45,6 +45,9 @@
 #define	G_LABEL_UFS_VOLUME	0
 #define	G_LABEL_UFS_ID		1
 
+#define G_LABEL_DIFF(a, b)	abs(a - b)
+#define G_LABEL_MAX_DIFF 	0x100
+
 static const int superblocks[] = SBLOCKSEARCH;
 
 static void
@@ -82,18 +85,28 @@
 		if (fs == NULL)
 			continue;
 		/*
-		 * Check for magic. We also need to check if file system size is equal
+		 * Check for magic. We also need to check if file system size is almost equal
 		 * to providers size, because sysinstall(8) used to bogusly put first
 		 * partition at offset 0 instead of 16, and glabel/ufs would find file
 		 * system on slice instead of partition.
+		 *
+		 * In addition, media size can be a bit bigger than file system size. For instance,
+		 * mkuzip can append bytes to align data to large sector size (it improves
+		 * compression rates).
 		 */
+		if (fs->fs_magic == FS_UFS1_MAGIC || fs->fs_magic == FS_UFS2_MAGIC){
+			G_LABEL_DEBUG(1, "%s %s params: %jd, %d, %d, %jd\n",
+					    fs->fs_magic == FS_UFS1_MAGIC ? "UFS1" : "UFS2", pp->name,
+					    pp->mediasize, fs->fs_fsize, fs->fs_old_size, fs->fs_providersize);
+		}
+
 		if (fs->fs_magic == FS_UFS1_MAGIC && fs->fs_fsize > 0 &&
-		    ((pp->mediasize / fs->fs_fsize == fs->fs_old_size) ||
-		    (pp->mediasize / fs->fs_fsize == fs->fs_providersize))) {
+		    ((G_LABEL_DIFF(pp->mediasize / fs->fs_fsize, fs->fs_old_size) < G_LABEL_MAX_DIFF) ||
+		    (G_LABEL_DIFF(pp->mediasize / fs->fs_fsize, fs->fs_providersize) < G_LABEL_MAX_DIFF))) {
 		    	/* Valid UFS1. */
 		} else if (fs->fs_magic == FS_UFS2_MAGIC && fs->fs_fsize > 0 &&
-		    ((pp->mediasize / fs->fs_fsize == fs->fs_size) ||
-		    (pp->mediasize / fs->fs_fsize == fs->fs_providersize))) {
+		    ((G_LABEL_DIFF(pp->mediasize / fs->fs_fsize, fs->fs_size) < G_LABEL_MAX_DIFF) ||
+		    (G_LABEL_DIFF(pp->mediasize / fs->fs_fsize, fs->fs_providersize) < G_LABEL_MAX_DIFF))) {
 		    	/* Valid UFS2. */
 		} else {
 			g_free(fs);