X86_64 build of 21.02 doesn't boot because ubus exits with error code 32512

I had the very same issue back in August: Init routine goes into loop when trying to execute ubus with custom image for Deco M4R

I too used Ubuntu in a VM as build host.

Happend with the master branch and 21.02-rc4 as well.

Never figured out why and thus my devices are still running on 19.07.8.

But that sounds like I should just set up a Debian VM and install the same stuff as on the Ubuntu VM? Can it be that simple?