diff --git a/scripts/build/binary_hdd b/scripts/build/binary_hdd
index 8d24586c8..c68c45129 100755
--- a/scripts/build/binary_hdd
+++ b/scripts/build/binary_hdd
@@ -187,7 +187,7 @@ case "${LB_BUILD_WITH_CHROOT}" in
 		Chroot chroot "parted -s ${FREELO} set 1 lba off" || true
 
 		if [ "${LB_BOOTLOADER_BIOS}" = "syslinux" ]; then
-			dd if=chroot/usr/lib/$(echo ${_BOOTLOADER} | tr [a-z] [A-Z])/mbr.bin of=${FREELO} bs=440 count=1
+			dd if=chroot/usr/lib/$(echo ${_BOOTLOADER} | tr '[a-z]' '[A-Z]')/mbr.bin of=${FREELO} bs=440 count=1
 		fi
 		;;
 
@@ -206,7 +206,7 @@ case "${LB_BUILD_WITH_CHROOT}" in
 		parted -s "${FREELO}" set 1 lba off || true
 
 		if [ "${LB_BOOTLOADER_BIOS}" = "syslinux" ]; then
-			dd if=/usr/lib/$(echo ${_BOOTLOADER} | tr [a-z] [A-Z])/mbr.bin of=${FREELO} bs=440 count=1
+			dd if=/usr/lib/$(echo ${_BOOTLOADER} | tr '[a-z]' '[A-Z]')/mbr.bin of=${FREELO} bs=440 count=1
 		fi
 		;;
 esac
diff --git a/scripts/build/binary_syslinux b/scripts/build/binary_syslinux
index 9b3d18ece..e21360af9 100755
--- a/scripts/build/binary_syslinux
+++ b/scripts/build/binary_syslinux
@@ -93,7 +93,7 @@ else
 fi
 
 # Checking depends
-Check_package chroot /usr/lib/$(echo ${_BOOTLOADER} | tr [a-z] [A-Z]) ${_BOOTLOADER}
+Check_package chroot /usr/lib/$(echo ${_BOOTLOADER} | tr '[a-z]' '[A-Z]') ${_BOOTLOADER}
 Check_package chroot /usr/lib/syslinux syslinux-common
 Check_package chroot /usr/bin/rsvg-convert librsvg2-bin