diff --git a/src/bin/mkdos/mkdos.cpp b/src/bin/mkdos/mkdos.cpp
index 3ca3323b51..b6e391053c 100644
--- a/src/bin/mkdos/mkdos.cpp
+++ b/src/bin/mkdos/mkdos.cpp
@@ -198,13 +198,16 @@ status_t Initialize(int fatbits, const char *device, const char *label, bool nop
 	if (!isRawDevice && !hasPartitionInfo) {
 		fprintf(stderr,"Warning: couldn't get partition information\n");
 	}
-	if (	(hasPartitionInfo && partitionInfo.logical_block_size != 512) 
-		||	(hasBiosGeometry && biosGeometry.bytes_per_sector != 512) 
+	if ((hasBiosGeometry && biosGeometry.bytes_per_sector != 512) 
 		||	(hasDeviceGeometry && deviceGeometry.bytes_per_sector != 512)) {
-		fprintf(stderr,"Error: block size not 512 bytes\n");
+		fprintf(stderr,"Error: geometry block size not 512 bytes\n");
 		close(fd);
 		return B_ERROR;
+	} else if (hasPartitionInfo && partitionInfo.logical_block_size != 512) {
+		printf("partition logical block size is not 512, it's %ld bytes\n",
+			partitionInfo.logical_block_size);
 	}
+
 	if (hasDeviceGeometry && deviceGeometry.read_only) {
 		fprintf(stderr,"Error: this is a read-only device\n");
 		close(fd);
@@ -321,7 +324,7 @@ status_t Initialize(int fatbits, const char *device, const char *label, bool nop
 	uint8 biosDriveId;
 
 	// get bios drive-id, or use 0x80
-	if (B_OK != ioctl(fd, B_GET_BIOS_DRIVE_ID, &biosDriveId)) {
+	if (B_OK != ioctl(fd, B_GET_BIOS_DRIVE_ID, &biosDriveId, sizeof(biosDriveId))) {
 		biosDriveId = 0x80;
 	} else {
 		printf("bios drive id: 0x%02x\n", (int)biosDriveId);