"unable to allocate CUDA0 buffer" after Updating Ubuntu Packages

I wonder if rollback the nvidia-l4t-firmware:arm64 package to version 36.4.4-20250616085344 from 36.4.7-20250918154033 would help?

I have not tried, but seems there are some folks that have explored this option.

Of course one runs the risk of an finding the jetson in unrecoverable state.