Imac with K1000m won't start after patches

Hi, I'm having troubles patching Sequoia on 27" imac (mid 2011).

After the complete installation of Sequoia and after patching the system with the oclp app, imac won't boot and remains stuck on the progress bar.

So I swapped the GPU with a K1100m from another imac and it boot normally with the same disk..

Boot the vga are flashed (by nick D vb) and the k1000m works witouth patches.

What could be? Any ideas how to make k1000m working with patched sequoia?

Thanks