rpi4 - strange video problem

Have a strange video issue with my RPi4B 4GB running ROOL RISC OS 5.30
When I boot up the machine the graphics on screen appear to be missing the red component – ie the raspberry pi which is usually red appears purple (same with all graphics).

My config.txt file is the same as on my RPi4b 8Gb (in a Deskpi pro cae) – this one does not have the same issue.

Things I have tried and haven’t made any difference:
- modified the config.txt file to add confi_hdmi_boost=4 (and tried higher values too)
- swapped 3 different HDMI cables
- connected to a different monitor using HDMI cable and then DVI cable via HDMI>DVI adapter
- tried higher power PSU (so not an undervoltage issue)
- bought and tried a completely different Rpi 4B as thought the board was faulty, not likely that 2 independently sourced Pi have the same issue (1 s/h the other brand new)

Interestingly when i connect to the RPi via a VNC session the colours displayed in the VNC session are correct.

Anyone else had this problem – how do you solve it – i seem to be hitting a wall at the moment with finding a solution.

Cheers
Jock

There’s a bug in recent START4.ELF builds – it no longer honours the “framebuffer_swap=0” line in config.txt.

Workaround is to download the 29 February 2024 build of both start4.elf and fixup4.dat. The process is explained on this page.

First firmware bug to bite us in quite a while…