Comment # 16 on bug 1132943 from Michael Hirmke

(In reply to Jiri Slaby from comment #15)
> (In reply to Michael Hirmke from comment #14)
> > Can't boot this kernel because of signature verification failure 8-(
> > This is a secure boot system.
> 
> So could you either disable secure boot for a minute or install the
> Takashi's certificate?
> 
> For the latter:
> osc signkey --sslcert home:tiwai |openssl x509 -outform DER -out /tmp/tiw
> mokutil --import /tmp/tiw

ok, I switched off secure boot for the moment.
Booting your 5.0.9 kernel gives the same error messages as 5.0.8 does.
5.0.7 still working without any problem.