With the latest android-tools 33.0.3, creating a boot image using mkbootimg is broken with this error:
Traceback (most recent call last):
File "/usr/bin/mkbootimg", line 31, in <module>
from gki.generate_gki_certificate import generate_gki_certificate
ModuleNotFoundError: No module named 'gki'
This issue does not happen in android-tools 31.0.3.