diff --git a/src/mkfs.fat.c b/src/mkfs.fat.c

index a7609b0..26ce3fd 100644

--- a/src/mkfs.fat.c

+++ b/src/mkfs.fat.c

@@ -517,6 +517,7 @@ static void establish_params(struct device_info *info)

     unsigned int heads = 255;

     unsigned int media = 0xf8;

     unsigned int cluster_size = 4;  /* starting point for FAT12 and FAT16 */

+    unsigned int sector_size_mult = 1; /* x 512 == sector_size */

     int def_root_dir_entries = 512;

     if (info->size < 512 * 1024 * 1024) {

@@ -590,11 +591,15 @@ static void establish_params(struct device_info *info)

 	 * fs size >   32G:  32k clusters

 	 *

 	 * This only works correctly for 512 byte sectors!

+	 * For other sector sizes it tries to approximate.

 	 */

 	uint32_t sz_mb = info->size / (1024 * 1024);

+	if (info->sector_size > 0)

+	    sector_size_mult = info->sector_size / 512;

 	cluster_size =

-	    sz_mb > 32 * 1024 ? 64 : sz_mb > 16 * 1024 ? 32 : sz_mb >

-	    8 * 1024 ? 16 : sz_mb > 260 ? 8 : 1;

+	    sz_mb > 32 * 1024 * sector_size_mult ? 64 : sz_mb >

+	    16 * 1024 * sector_size_mult ? 32 : sz_mb >

+	    8 * 1024 * sector_size_mult ? 16 : sz_mb > 260 * sector_size_mult ? 8 : 1;

     }

     if (info->geom_heads > 0) {