Based upon https://en.opensuse.org/openSUSE:UEFI I was able to
# efibootmgr -c -L "opensusetw" -l '\EFI\opensusetw\grubx64.efi' # efibootmgr BootCurrent: 0004 Timeout: 1 seconds BootOrder: 0000,0004,0005,0003 Boot0000* opensusetw Boot0003* CD/DVD Drive Boot0004* UEFI OS Boot0005* Hard Drive
Prior to the swap, TW’s Grub menu began approximately as follows:
memtest86 7.4 EFI openSUSE TW openSUSE 15.0 openSUSE 15.1 Debian 10 Buster Tubuntu 18.04 Linuxmint 19 etc.
This was restored by the above efibootmgr -c command.
The proximate cause of need was something I didn’t save, but the following template would be close enough:
# efibootmgr BootCurrent: 0000 Timeout: 1 seconds BootOrder: 0000,0001,0002,0004,0005,0003 Boot0000* ubuntu Boot0001* ubuntu Boot0002* ubuntu Boot0003* CD/DVD Drive Boot0004* UEFI OS Boot0005* Hard Drive
How it got that way was a consequence of my UEFI installation media => Boot Linux System thread setup, removing the SSD, attaching an empty HD in its place, installing 15.2, then testing “Boot Linux System” from installation media.
How those three ubuntu entries got there I can’t say. I suppose they were in the back reaches of NVRAM, put there when Kubuntu and Mint got installed, after TW and 15.0 and 15.1 and Debian, and subsequently upgraded, even though I removed all its and Debian’s entries using efibootmgr, and even though I purged bootloader packages from all installations except TW. At least, I thought I purged it from all other. And, even though I adjusted most fstabs, including Kubuntu’s and Mint’s, except TW’s by commenting each ESP partition entry, so that /boot/efi/ when running would not provide access to the ESP except when TW is running.
On first boot after reconnecting the SSD, I expected to get the same UEFI presentation as I had been for more than a year before the storage switch. Instead, I got a grub> prompt. On restart I hit F8 to get the Asus boot menu, whereupon I found no sign of any openSUSE selection, only devices (ordinary and UEFI USB sticks; ordinary and UEFI SATA (SATA6G_3), and multiple ubuntu entries). I chose the UEFI OS entry (0004), and got another grub> prompt. From there I typed in the text of the default selection from a backup copy of grub.cfg, which got me TW booted, apparently normally. Once I found the wiki page, I found its example and used it to add the needed entry that begins this post.
Already I’ve forgotten exactly what happened next, but eventually I rebooted into BIOS again. In UEFI Hard Drive Priorities, only one was listed, UEFI OS (SATA6G_3 <model#>). I selected that entry and was presented both it and opensusetw to select from. I selected opensusetw, with result that there were now two boot options, with opensusetw first, and booting is back to normal via TW’s grub configuration.
Asus Aptio/AMI BIOS date is 20181116, Version 1402 x64, ME Firmware version 126.96.36.19910, PCH Stepping AO.
Anyone know if mangling of UEFI entries as happened to me today is typical of disk swaps in UEFI PCs?