MX-21.2.1_ahs_x64 boot fails; vmlinuz has invalid signature [Solved]

[carolus]

This problem has been reported in the past and appears to be connected with secure boot. It occurs on two Windows 10 computers but not on a Windows 7 computer. However, it does not occur with MX18 or with a fully upgraded standard MX21, only with the AHS version. The USB drive itself is probably not defective since it boots a Windows 7 computer.

I was trying the AHS version since the standard version does not seem to support the Mediatek MT7921 wireless card in a new computer. However, the AHS version seems to lack the tricks for handling secure boot that were present in previous versions.

[dolphin_oracle]

the ahs kernels are not signed, and as such will not boot with secure boot. even if we signed them, they wouldn't boot with debian's secure-boot shim.