Code 43 is exactly the problem with the modified driver. Solutions to problems 2. I know because I faced such a problem.
Yeah, except the same code 43 error also sometimes shows up in nvidia rigs as well. 
Which don't have modified BIOS'es or patchers. Code 43 error is: "Windows has stopped this device because it has reported problems". There's a buttload of reasons for this to happen, not patched AMD drivers with modified BIOS is only one of them.