Hi Stefan, On 23/12/2019 19:51, Stefan Wahren wrote: > Am 20.12.19 um 14:58 schrieb Stefan Wahren: >> Hi, >> >> i tried to run current U-Boot (rpi_4_32b_defconfig) on my RPi 4 with >> bcm2711-rpi-4-b.dtb from the upstream kernel. Unfortunately i only see >> garbage on the debug UART (pin 14 & 15). Using the DTB from the >> downstream kernel has a proper UART output. The config.txt contains >> debug_uart=1 >> >> I compared both and identified an offending Linux commit: >> ARM: dts: bcm283x: Remove brcm,bcm2835-pl011 compatible >> >> Unfortunately reverting this patch still doesn't fix the issue. Any ideas? > > After hours of playing with the DTB, i finally found the reason why the > upstream kernel DTB doesn't work with U-Boot on RPI 4. The DTS must be > compiled with flag "-@". > > It isn't clear to me, why this is necessary but it would be nice to make > U-Boot work without this. >
Can you provide the exact command you are using? Regards, Matthias
