Loading display drivers in initrd (~3s) before RP1 PCIe southbridge is ready (~12s) causes 'Cannot find any crtc or sizes' because the DSI encoder isn't reachable. Rex loads these via udev late in boot. - boot.initrd.kernelModules: only ocp8178_bl (backlight, RP1-independent) - boot.kernelModules: vc4 + panel_cwu50 loaded in stage 2 after RP1