diff --git a/reactos/lib/fslib/vfatlib/vfatlib.c b/reactos/lib/fslib/vfatlib/vfatlib.c
index b2a27332d06..d466e581d4c 100755
--- a/reactos/lib/fslib/vfatlib/vfatlib.c
+++ b/reactos/lib/fslib/vfatlib/vfatlib.c
@@ -426,6 +426,14 @@ VfatFormat(
       return Status;
     }
 
+  if (PartitionInfo.PartitionLength.QuadPart < 512ULL * 1024ULL * 1024ULL)
+    {
+      DPRINT1("FIXME: Partition size is smaller than 512MB - use FAT16\n");
+      NtClose(FileHandle);
+      return STATUS_UNSUCCESSFUL;
+    }
+
+
   /* Calculate cluster size */
   if (ClusterSize == 0)
     {
diff --git a/reactos/subsys/system/usetup/usetup.c b/reactos/subsys/system/usetup/usetup.c
index 42d678cd086..5765eb73af4 100644
--- a/reactos/subsys/system/usetup/usetup.c
+++ b/reactos/subsys/system/usetup/usetup.c
@@ -1596,16 +1596,16 @@ FormatPartitionPage (PINPUT_RECORD Ir)
 			    PartEntry->PartInfo[0].PartitionType = PARTITION_HUGE;
 			  }
 		      }
-		    else if (PartEntry->PartInfo[0].PartitionLength.QuadPart < (2ULL * 1024ULL * 1024ULL * 1024ULL))
+		    else if (PartEntry->PartInfo[0].PartitionLength.QuadPart < (512ULL * 1024ULL * 1024ULL))
 		      {
-		        /* FAT16 LBA partition (partition is smaller than 2GB) */
+		        /* FAT16 LBA partition (partition size is smaller than 512MB) */
 		        DPRINT1("%x\n", PartEntry->PartInfo[0].PartitionType);
 		        PartEntry->PartInfo[0].PartitionType = PARTITION_XINT13;
 		      }
 		    else
 		      {
 		        DPRINT1("%x\n", PartEntry->PartInfo[0].PartitionType);
-		        /* FAT32 LBA partition (partition is at least 2GB) */
+		        /* FAT32 LBA partition (partition size 512MB or larger) */
 		        PartEntry->PartInfo[0].PartitionType = PARTITION_FAT32_XINT13;
 		      }
 		    break;