I bisected again. It seems I made some mistake last time, as I got a different result this time. Maybe, because these problematic kernels may boot fine sometimes, like I said before.
Anyway, first bad commit (makes much more sense this time): e7b813b32a42a3a6281a4fd9ae7700a0257c1d50 efi: random: refresh non-volatile random seed when RNG is initialized
I confirmed that this is the code causing the issue by commenting it out (see the patch file). Without this code, the latest mainline boots fine.
Terveisin Sami Korkalainen