put memtest on boot-drive (in boot/EFI/memtest) and add to uefi boot menu (may need to disable secure UEFI boot)

memtest-uefi-menu.sh

# wget    memtest86-usb.zip 
unzip  memtest86-usb.zip 
# 
testdisk memtest85-usb.img

mkdir /tmp/memtest
# use testdisk or similar to extract files in /EFI/BOOT/ on partition 1 to /tmp/memtest/

$ tree /tmp/memtest/
/tmp/memtest/
└── EFI
    └── BOOT
        ├── Benchmark
        ├── blacklist.cfg
        ├── BOOTAA64.efi
        ├── BOOTIA32.efi
        ├── BOOTX64.efi
        ├── mt86.png
        └── unifont.bin
        
mkdir /boot/efi/EFI/memtest/
# ls /boot/efi/EFI
Boot  debian  memtest  Microsoft  sparky

mv /tmp/memtest/EFI/BOOT/*   /boot/efi/EFI/memtest/
# ls -l /boot/efi/EFI/memtest/
total 6001
drwx------ 2 root root    1024 Feb 14 03:16 Benchmark
-rwx------ 1 root root    4771 Feb 14 02:45 blacklist.cfg
-rwx------ 1 root root 1098096 Feb 14 02:45 BOOTAA64.efi
-rwx------ 1 root root 1208752 Feb 14 02:45 BOOTIA32.efi
-rwx------ 1 root root 1317616 Feb 14 02:45 BOOTX64.efi
-rwx------ 1 root root    6823 Feb 14 02:45 mt86.png
-rwx------ 1 root root 2355408 Feb 14 02:45 unifont.bin

efibootmgr --create --disk /dev/sda --part 2 --loader /EFI/memtest/BOOTX64.efi --label "memtest"
### need lower memtest menu-item down the list if it is first menu-item (can do in bios->Startup)

# reboot and hit F12 to get to UEFI boot menu, then choose memtest

ToDo: flesh-out into actual shell script and add quickstart instructions.

And/Or, on UEFI pcs, you can use refind boot manager that will automatically add menu-item to run memtest per https://wiki.archlinux.org/index.php/rEFInd#Memtest86