Octoprint Pi 4 USB web cam and Fixing wifi loss

I've noticed to get a USB webcam working on a Pi I need to have the 3D printer turned on with a valid connection to the Pi, in order to actually view the stream. Is this by design ? As the Pi is connected to the camera via USB, and shouldn't need a connection to the printer at all.

Anyway I hit another problem with installation, as my Pi 4 running Octoprint Pi 4 was losing comms to my PC, and hence the web portal.

If you find that you lose comms to your Raspberry Pi 4 while running Octoprint, connect via head mode (ie with HDMI, keyboard, mouse etc). Then check the messages in the linux log

sudo dmesg | grep brcmf

If you see any errors with -110, then the wifi firmware has crashed

ieee80211 phy0: brcmf_run_escan: error (-110)
ieee80211 phy0: brcmf_cfg80211_scan: scan error (-110)

This seems to be a problem with the latest Octoprint Pi image

OctoPrint Version 1.7.2
OctoPi version 0.18.0

You can repair it by downloading and copying the latest wifi firmware into the following folder

cd /lib/firmware/brcm

Backup original firmware first

sudo cp brcmfmac43455-sdio.bin brcmfmac43455-sdio.bin.orig

Then download the fixed one from here (or find a legitimate source)

New Wifi FW

And copy the downloaded firmware into the lib folder

sudo cp ~/Downloads/ brcmfmac43455-sdio.bin /lib/firmware/brcm/.


sudo reboot

You can find the full problem and solution on this thread

Hope this helps anyone losing connection, and also viewing the web cam stream !