Bug#984760: grub-pc: upgrade works, boot fails (error: symbol `grub_is_lockdown` not found)

[Ryan Thoryk]

I have something to add to this.  This morning I was writing up a 
document on how to convert an existing Debian amd64 AWS VM to arm64 
without reinstalling, which is something I was interested in doing in 
the future to a fairly complex system install that I wasn't excited 
about trying to reinstall/migrate.  Everything worked with the 
conversion, except for the grub stage, grub failed to start on the ARM 
instance and was stuck at the grub-rescue prompt.  When typing "insmod 
normal", it shows the "symbol `grub_is_lockdown` not found" error.  I 
managed to get it working by copying grub modules from an existing 
Debian ARM VM over to it, I did that because I noticed that the modules 
were of a newer version and a different size.

I'm not sure if the "grub-install" step was needed, but after 
investigating I found that when I ran grub-install a standard 
Debian-provided ARM AWS community instance and rebooted, the instance 
fails to boot in the same way.

This is my document if you were interested, I mention the error in it:
https://ryan.thoryk.com/linux/arm_convert.html

-- 
Ryan Thoryk
ryan at thoryk.com
ryan at tliquest.net