I'm assuming you have non-free-firmware enabled for both Debian 12 and 13, so the drivers are accessing the i915 firmware OK?
Can you install the Debian 12 kernel and module packages (6.1.153-1), and boot Debian 13 with Debian 12's kernel -- does that work?
I suppose another data-point would be, if you installed the backports version of the kernel on Debian 12 (6.12.43-1~bpo12+1) -- does that boot and function properly?
-- Jonathan Dowland [email protected] https://jmtd.net
