Garbage output on HDMI

[Stefan Wahren]

Hi,

i'm still using a Raspberry Pi B with latest firmware, latest U-Boot (second stage bootloader) and mainline kernel (tested 4.4, 4.8, 4.9). If i connect the Pi via HDMI i only get a garbage output [1] with the combination above. But the system works as expected if i connect via debug UART.

If i replace u-boot with the vendor kernel instead everything is displayed on HDMI as expected.

Any ideas what is the problem? I know it worked before.

[1] - https://i.imgsafe.org/919c7e7e89.jpg