diff --git a/build/jam/ImageRules b/build/jam/ImageRules
index 65c6f07b8b..80373dc141 100644
--- a/build/jam/ImageRules
+++ b/build/jam/ImageRules
@@ -1574,7 +1574,7 @@ actions BuildFloppyBootImage1
 	fi
 	$(RM) $(<)
 	# make an empty image
-	dd if=/dev/zero of=$(<) bs=1k count=$(FLOPPY_IMAGE_SIZE)
+	dd if=/dev/zero of=$(<) bs=1024 count=$(FLOPPY_IMAGE_SIZE)
 	# add haiku_loader
 	dd if=$(>[1]) of=$(<) conv=notrunc
 	# add the boot drivers tgz archive
diff --git a/build/jam/images/MMCImage b/build/jam/images/MMCImage
index 17f037df14..b11bc1f048 100644
--- a/build/jam/images/MMCImage
+++ b/build/jam/images/MMCImage
@@ -62,7 +62,7 @@ actions BuildUBootSDImage1
 	MMC_SIZE=`expr $(SDIMAGE_OS_SIZE) \* 1024 + ${BOOT_SIZE}`
 
 	# Build "boot" disk
-	dd if=/dev/zero of=$(1) bs=1K count=${BOOT_SIZE}
+	dd if=/dev/zero of=$(1) bs=1024 count=${BOOT_SIZE}
 
 	# generate u-boot environment variables
 	echo 'os=haiku' > uEnv.txt
@@ -122,7 +122,7 @@ actions BuildEfiSDImage1
 	MMC_SIZE=`expr $(SDIMAGE_OS_SIZE) \* 1024 + ${BOOT_SIZE}`
 
 	# Build "boot" disk
-	dd if=/dev/zero of=$(1) bs=1K count=${BOOT_SIZE}
+	dd if=/dev/zero of=$(1) bs=1024 count=${BOOT_SIZE}
 
 	# generate u-boot environment variables
 	echo 'os=haiku' > uEnv.txt
diff --git a/src/system/boot/platform/atari_m68k/mk_floppy_prg_atari.sh b/src/system/boot/platform/atari_m68k/mk_floppy_prg_atari.sh
index 1facd413d2..2f0fed5738 100755
--- a/src/system/boot/platform/atari_m68k/mk_floppy_prg_atari.sh
+++ b/src/system/boot/platform/atari_m68k/mk_floppy_prg_atari.sh
@@ -2,7 +2,7 @@
 IMG=$HOME/floppy.img
 ZBEOS=haiku_loader
 jam -q haiku.prg $ZBEOS && \
-dd if=/dev/zero of=$IMG bs=1k count=1440 && \
+dd if=/dev/zero of=$IMG bs=1024 count=1440 && \
 dd if=generated/objects/haiku/m68k/release/system/boot/$ZBEOS of=$IMG bs=512 conv=notrunc && \
 src/system/boot/platform/atari_m68k/fixup_tos_floppy_chksum $IMG && \
 true