diff --git a/extensions/grub.sh b/extensions/grub.sh
index 878d1ab2bc..1eedbc0872 100644
--- a/extensions/grub.sh
+++ b/extensions/grub.sh
@@ -101,7 +101,7 @@ pre_umount_final_image__install_grub() {
 		}
 	fi
 
-	local install_grub_cmdline="update-initramfs -c -k all && update-grub && grub-install --verbose --target=${UEFI_GRUB_TARGET} --no-nvram --removable" # nvram is global to the host, even across chroot. take care.
+	local install_grub_cmdline="update-grub && grub-install --verbose --target=${UEFI_GRUB_TARGET} --no-nvram --removable" # nvram is global to the host, even across chroot. take care.
 	display_alert "Installing GRUB EFI..." "${UEFI_GRUB_TARGET}" ""
 	chroot "$chroot_target" /bin/bash -c "$install_grub_cmdline" >>"$DEST"/"${LOG_SUBPATH}"/install.log 2>&1 || {
 		exit_with_error "${install_grub_cmdline} failed!"
diff --git a/lib/debootstrap.sh b/lib/debootstrap.sh
index 9f6a299a8d..de98f9a0ca 100644
--- a/lib/debootstrap.sh
+++ b/lib/debootstrap.sh
@@ -763,7 +763,7 @@ update_initramfs()
 		find ${chroot_target}/lib/modules/ -maxdepth 1 -type d -name "*${VER}*"
 	)
 	if [ "$target_dir" != "" ]; then
-		update_initramfs_cmd="update-initramfs -uv -k $(basename $target_dir)"
+		update_initramfs_cmd="TMPDIR=/tmp update-initramfs -uv -k $(basename $target_dir)"
 	else
 		exit_with_error "No kernel installed for the version" "${VER}"
 	fi
diff --git a/lib/image-helpers.sh b/lib/image-helpers.sh
index 344d9a79ca..0619621c81 100644
--- a/lib/image-helpers.sh
+++ b/lib/image-helpers.sh
@@ -33,6 +33,7 @@ mount_chroot()
 {
 
 	local target=$1
+	mount -t tmpfs tmpfs "${target}/tmp"
 	mount -t proc chproc "${target}"/proc
 	mount -t sysfs chsys "${target}"/sys
 	mount -t devtmpfs chdev "${target}"/dev || mount --bind /dev "${target}"/dev
@@ -52,11 +53,12 @@ umount_chroot()
 
 	local target=$1
 	display_alert "Unmounting" "$target" "info"
-	while grep -Eq "${target}.*(dev|proc|sys)" /proc/mounts
+	while grep -Eq "${target}/*(dev|proc|sys|tmp)" /proc/mounts
 	do
 		umount -l --recursive "${target}"/dev >/dev/null 2>&1
 		umount -l "${target}"/proc >/dev/null 2>&1
 		umount -l "${target}"/sys >/dev/null 2>&1
+		umount -l "${target}"/tmp >/dev/null 2>&1
 		sleep 5
 	done