參考了將Clonezilla Live放在硬碟中及【教學】把系統還原軟體 Clonezilla 放在硬碟中（4/15更新）

　　將SSD外接式硬碟安裝了ubuntu 20.04後在根目錄下建立了clonezilla目錄，並把clonezilla-live-2.6.7-28-amd64.zip解壓到裡面。也編輯了/etc/grub.d/40_custom及/etc/default/grub兩個檔案後update-grub。

　　但是重新開機後未見grub2選單，只看到背景圖片(Moraine_Lake_17092005.tga)，幾秒之後就直接開機進入ubuntu了，請教前輩達人們可否解惑？

　　※備註：在內接機械SATA硬碟以相同作法是可以出現grub2開機選單(Ubuntu、Windows 10、再生龍都可以開機)。

ubuntu@ubuntu:~$ ls /clonezilla
amd64-release.txt  boot  Clonezilla-Live-Version  EFI  GPL  home  live-hd  syslinux  utils

ubuntu@ubuntu:~$ blkid
/dev/sda2: UUID="6568fcf1-f60e-4821-87e2-11e2561a6c47" TYPE="ext4" PARTUUID="28801a6f-82dc-4f8c-a043-44d45baba619"
/dev/loop0: TYPE="squashfs"
/dev/loop1: TYPE="squasclonezillzhfs"
/dev/loop2: TYPE="squashfs"
/dev/loop3: TYPE="squashfs"
/dev/loop4: TYPE="squashfs"
/dev/loop5: TYPE="squashfs"
/dev/loop6: TYPE="squashfs"
/dev/loop7: TYPE="squashfs"
/dev/sda1: UUID="F751-810F" TYPE="vfat" PARTUUID="5d0de414-f1e6-4376-9cfa-7c2b19ba64cf"
/dev/sda3: LABEL="clonezillaBackup" UUID="d9b246ac-e568-44fe-8dac-9aadfeab72a8" TYPE="ext4" PARTLABEL="clonezillaBackup" PARTUUID="9d227970-07b1-4836-a605-0b0c5cb5de2f"
/dev/loop8: TYPE="squashfs"

ubuntu@ubuntu:~$ cat /etc/grub.d/40_custom 
#!/bin/sh
exec tail -n +3 $0
# This file provides an easy way to add custom menu entries.  Simply type the
# menu entries you want to add after this comment.  Be careful not to change
# the 'exec tail' line above.
menuentry "再生龍" {
search --no-floppy --fs-uuid --set=root 6568fcf1-f60e-4821-87e2-11e2561a6c47
linux /clonezilla/live-hd/vmlinuz live-media-path=/clonezilla/live-hd toram=filesystem.squashfs boot=live union=overlay username=user config components quiet noswap edd=on nomodeset enforcing=0 noeject locales=zh_TW.UTF-8 keyboard-layouts=NONE ocs_live_run=\"ocs-live-general\" ocs_live_extra_param=\"\" ocs_live_batch=\"no\" vga=786 ip= net.ifnames=0 splash i915.blacklist=yes radeonhd.blacklist=yes nouveau.blacklist=yes vmwgfx.enable_fbdev=1
initrd /clonezilla/live-hd/initrd.img
}

ubuntu@ubuntu:~$ cat /etc/default/grub

GRUB_DEFAULT=0
GRUB_TIMEOUT_STYLE=hidden
GRUB_TIMEOUT=30
GRUB_DISTRIBUTOR=`lsb_release -i -s 2> /dev/null || echo Debian`
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"
GRUB_CMDLINE_LINUX=""

ubuntu@ubuntu:~$ sudo update-grub
Sourcing file `/etc/default/grub'
Sourcing file `/etc/default/grub.d/init-select.cfg'
正在產生 grub 設定檔 ...
Found background image: Moraine_Lake_17092005.tga
找到 linux 映像檔：/boot/vmlinuz-5.4.0-52-generic
找到 initrd 映像檔：/boot/initrd.img-5.4.0-52-generic
找到 linux 映像檔：/boot/vmlinuz-5.4.0-42-generic
找到 initrd 映像檔：/boot/initrd.img-5.4.0-42-generic
Adding boot menu entry for UEFI Firmware Settings
完成