My system does indeed boot with this fix!
Unfortunately, there is some other kernel breakage with linux-image-5.13.0-1007-raspi which is killing any display output and forcing me to do a hard reset to reboot the system.
So I've opened a separate bug for that here: https://bugs.launchpad.net/ubuntu/+source/linux-raspi/+bug/1944397
My system does indeed boot with this fix!
Unfortunately, there is some other kernel breakage with linux-image- 5.13.0- 1007-raspi which is killing any display output and forcing me to do a hard reset to reboot the system.
So I've opened a separate bug for that here: https:/ /bugs.launchpad .net/ubuntu/ +source/ linux-raspi/ +bug/1944397