I have tried generating a bookworm-minbase-ab.yaml config based image for the CM4 and CM5 but this fails due to a error installing mmc-utils as tried in file image/gpt/ab_userdata/bdebstrap/customize03-emmc-ops https://github.com/raspberrypi/rpi-image-gen/blob/master/image/gpt/ab_userdata/bdebstrap/customize03-emmc-ops apt fails to download the deb package
as a workaround adding mmc-utils as an additional package to one of the upper layers for e.g. ab-slots.yml works. but probably a better fix is feasible. this is my first time using the tool so not sure what the correct fix would be.
This was tried on a CM5 system running bookworm.