Comment # 31 on bug 1175908 from Harald Koenig

(In reply to Takashi Iwai from comment #30)
> Well, I'm no expert in this area at all, so not the best person to ask...
> 
> In anyway, Harald, could you test the recent TW live image or a rescue
> image, and verify whether you can mount the partition manually from there? 
> If it works, we can compare what's missing.

VERY good idea, thanks!

openSUSE-Tumbleweed-XFCE-Live-x86_64-Snapshot20200831-Media.iso works, can open
encrypted fs.

lsmod shows 188 modules. I've created an initrd with all 188 modules with
dracut --install mod1 ...
this still does not work. but provides lots of files for more testing in initrd
;)

loading all kernel/crypto/* with insmod  works.

rebooting and loading those modules one by one shows that essiv.ko.xz is
needed.
but just "modprobe essiv" complains about missing symbol.
only after "depmod -a" this modprobe works and cryptsetup open too.

now I've created a new initrd with

     dracut  --add-drivers  essiv   --kver 5.8.4-1-default --force

and boot works!!!


questions remaining: 

why did this happen ?
what's the right way to fix this for the future ?


a big THANKS for your help and input!