Has anyone managed to boot the mainline kernel (from kernel.org, not RPi vendor fork) on the Raspberry Pi4 with its native bootloader ?
Without an initrd → black screen.
With initrd + followkernel param → rainbow screen.
No serial output in either case.
I'm using the correct DTB.
Same mainline kernel boots when chainloaded via U-Boot (as we do for Slackware on the RPi4).
I haven’t seen any recent reports of anyone getting this working — has anyone?