I’ll keep taking notes here, as much for my reference. I’m hopeful this is recoverable because Manjaro works well. I can use a microSD card with a fresh Manjaro installation and it works perfectly again until I run sudo pacman -Syu; it’s something about whatever is getting updated (I think the kernel?) that’s playing hob.
[manjaro /]# efibootmgr
BootCurrent: 0003
Timeout: 0 seconds
BootOrder: 0002,2001,0004,0001,0000,2002,2003
Boot0000* EFI Hard Drive (22204M51227914-Phison ESMP512GKB4C3-E13TS) PciRoot(0x0)/Pci(0x1,0x2)/Pci(0x0,0x0)/NVMe(0x1,64-79-A7-64-AA-20-0E-61)/HD(1,GPT,27bd1145-0922-a94f-b256-8df6bd39e819,0x800,0x20000)RC
Boot0001* SteamOS HD(1,GPT,27bd1145-0922-a94f-b256-8df6bd39e819,0x800,0x20000)/File(\EFI\steamos\steamcl.efi)
Boot0002* EFI SD/MMC Card (DS 821R ﾱ￭ﾆ) PciRoot(0x0)/Pci(0x1,0x3)/Pci(0x0,0x0)/SD(0)/HD(1,GPT,76d30e90-f760-e24a-af47-d29bc55e1448,0x1000,0x96000)RC
Boot0003* EFI USB Device (USB DISK 3.0) UsbWwid(13fe,6300,0,0700036E132A7A6)/CDROM(1,0x79b484,0x8000)RC
Boot0004* manjaro HD(1,GPT,76d30e90-f760-e24a-af47-d29bc55e1448,0x1000,0x96000)/File(\EFI\manjaro\grubx64.efi)
Boot2001* EFI USB Device RC
Boot2002* EFI DVD/CDROM RC
Boot2003* EFI Network RC
[manjaro /]# grub-emu
-> *Manjaro Linux
error: sparse file not allowed.
error: no such device: ********-****-****-****-************.
Following this response re: “error: sparse file not allowed” and modifying /etc/default/grub to use GRUB_SAVEDEFAULT=false and GRUB_DEFAULT=0 fixed one of the two errors from grub-emu:
[manjaro /]# grub-emu
-> *Manjaro Linux
error: no such device: ********-****-****-****-************.