firmware VS linux

the usual error is the image was made before the 8gb pi4 was released so is compatible with the 1,2 and 4gb models only without updating - for this error you can grab the latest boot file versions (kernel7l.img, start4.elf and the fixup4.dat are required for pi4) from here - https://github.com/raspberrypi/firmware/tree/master/boot - they go into the /boot partition of the microsd/usb/ssd overwriting the old versions.

But oddly enough, they don't support some screen resolutions: https://github.com/raspberrypi/firmware/issues/1202#issuecom...

i went with the classic, you just need their special boot firmware (everything but the kernels, dtbs and overlay folder)

USB3 and 2.4 GHz Wifi · Issue #1430 · raspberrypi/firmware

OK for anyone else experiencing this problem - seems to be due to a breaking change in Raspberry Pi OS! - https://github.com/raspberrypi/firmware/issues/1795

RetroArch can switch resolution like you said (https://github.com/libretro/RetroArch/pull/11590), and this fixes the bug (https://github.com/raspberrypi/firmware/issues/1357) that the new DRM interface does not work for switching DPI displays (like our SCART hats.

Based on https://github.com/raspberrypi/firmware/issues/1734 a kernel change may have caused my problem. I will check this tomorrow.

Those happened ~9 seconds after startup and it's a known error, so it's probably fine.

Fan control generally involves hysteresis. This means a cooling fan turns on at one temperature, and then turns off once temperature has fallen to another lower temperature. This avoids cycling the fan on and off too much. The difference between those two temperatures is hysteresis. The default hysteresis is 10°C and maybe the fan never manages to cool the CPU to 45°C. A parameter has been added to change hysteresis: https://github.com/raspberrypi/linux/commit/fa390133fd17f2cc6aa5a7d2e472c073a1115fe1

I see that the PR against the Raspberry Pi linux repo is out [0]. Interestingly they are introducing a BCM2712 defconfig with a 64k default page size.

[0] - https://github.com/raspberrypi/linux/pull/5618

and can grab their patched kernel source here ( use the dtbs and overlays and kernel from your compiled version)

Also was your pi issue related to this? https://github.com/raspberrypi/linux/issues/3381 or what do you mean jittery, unstable?

Could be related to the driver load order/blacklisting (https://github.com/raspberrypi/linux/issues/435) Or couple of people report configuring the dtoverlay=imx477 in the boot config helped (https://raw.githubusercontent.com/raspberrypi/firmware/master/boot/overlays/README)

thanks, I also found this: https://github.com/raspberrypi/linux/issues/5398

And ready! :)

> It is the most basic task for Linux computer...

Well, it depends for whom. Also, you need adequate software and hardware. About wireless, the chipset in an RPi4 is designed for clients, not APs, and its capabilities on having multiple clients are quite limited:

https://github.com/raspberrypi/linux/issues/3010

Routers like the Omnia Turris, Mikrotik, PC Engines... use specific mini PCIe cards that can be as expensive as a full Raspberry Pi 4, just for the wireless.

https://www.discomp.eu/wireless-minipci-cards_c14501412.html