Hi there,

I've installed Alpine Linux 3.11 several months ago on my Raspberry Pi
4 using the classical method described on the wiki [0].

After upgrading to 3.12, it still boots but the kernel hangs, last
lines shown are related to USB devices (but I guess this is unrelated,
none are connected, only HDMI cable). I think it does not even call the
init because I've tried booting with init=/bin/sh with the same result.

The last lines are:

...
[ 1.945569] hub-1-1:1.0: USB hub found
[ 1.945569] hub-1-1:1.0: 4 ports detected

Unfortunately I can't provide much more information as I can't even get
a shell to start, any help is welcome.

Regards,

[0]: 
https://wiki.alpinelinux.org/wiki/Classic_install_or_sys_mode_on_Raspberry_Pi

-- 
David