arm64 stable/13 boot stuck

From: Matthew Grooms <>
Date: Sat, 12 Jun 2021 22:28:54 UTC
I just updated my rpi4 kernel sources today and get this very early in my rpi4 boot output ...

bcm_mbox_write: STATUS_FULL stuck

If I roll back to 043f204985261d6daae69538c4609b3e143ee444 from yesterday, it boots fine again. I assume this is related to Andrew Turner's latest batch of arm64 commits.