diff --git a/src/system/boot/platform/u-boot/Jamfile b/src/system/boot/platform/u-boot/Jamfile
index f8fe507819..7ce4ed8623 100644
--- a/src/system/boot/platform/u-boot/Jamfile
+++ b/src/system/boot/platform/u-boot/Jamfile
@@ -151,7 +151,7 @@ actions BuildUImageScript1
 rule BuildUBootSDImage image : files
 {
 	Depends $(image) : $(files) ;
-	SDIMAGE_BLOCK_SIZE on $(image) = 1M ;
+	SDIMAGE_BLOCK_SIZE on $(image) = 1048576 ; # 1M
 	SDIMAGE_SIZE on $(image) = $(HAIKU_BOARD_SDIMAGE_SIZE) ;
 	SDIMAGE_FDISK on $(image) = $(HOST_SFDISK) ;
 	SDIMAGE_FDISK_SCRIPT on $(image) =