Use a tool like Monitor Asset Manager (Windows) or edid-decode (Linux) while the TR8303C V4 is connected. You are looking for the "Established Timings" block. If you see "720x400" or "640x480" as the primary timing, your code is bad.
He opened the raw kernel module—the tr8303c core. It was a dense jungle of logic gates and conditional loops. He began to rewrite, not the code itself, but the resolution layer wrapped around it. tr8303c v4 resolution code better