Hello Matthias, I have upgraded the Raspberry 3 firmware from raspi3-firmware (1.20190215-1+deb10u4) to raspi-firmware (1.20200601-3) [https://packages.debian.org/bullseye/raspi-firmware].
After the upgrade the output of U-Boot on the serial console is complete gibberish as if the baudrate were incorrect. The output from the Linux kernel is fine at 115200 baud. I observe this both with rpi_3_defconfig and rpi_arm64_defconfig, v2020.10 and current origin/master. config.txt: arm_control=0x200 enable_uart=1 upstream_kernel=1 kernel=u-boot.bin boot.scr: setenv autoload no dhcp load mmc 0:1 $fdt_addr_r bcm2710-rpi-3-b-plus.dtb load mmc 0:2 $kernel_addr_r EFI/debian/grubaa64.efi bootefi $kernel_addr_r $fdt_addr_r Best regards Heinrich
