The integrated wifi adapter stopped working after the upgrade to linux-armv7-5.6.7-1. There was an update to linux-firmware around the same time, but that doesn't seem to be the culprit. 5.6.2 works with both linux-firmware-20200316 and -20200421, while the new kernel works with neither version.
This is the error in dmesg, but that seems to be pretty generic, so I guess it won't help:
$this->bbcode_second_pass_code('', '
[ 28.647464] brcmfmac: brcmf_sdio_bus_rxctl: resumed on timeout
[ 28.728000] brcmfmac: brcmf_sdio_firmware_callback: brcmf_attach failed
')
The patch-5.6.4-armv7-x11.diff patchset that 5.6.7 switched to introduced a lot of changes to the brcm80211 driver, so I guess the problem might be there somewhere.
Is this a known problem? I guess not, as I also tested the current -rc package of the kernel (5.7.rc3 as of now), but that doesn't work neither.
Is there a way I can help to debug this? Doing so would probaly involve compiling my own kernel which brings me to these questions (please pardon my ignorance...):
1. Is the big debian patchset available as individual patches, preferably in a git repository?
2. What's the best/easiest way to cross-compile the kernel? Building on the cubietruck is probably a bit much...