Oh dear, not good, Chris.
1/. In future, if you ever get a warning when you're out flying that you need to update FW or app or anything else - DON'T DO IT - you can safely ignore those messages 'til you're home.
2/. You don't need to be connected to the internet to fly, so don't; put the phone / device in airplane mode.
3/. There are no
bad FW updates; if that was the case, everyone's AC / RC would be affected.
4/. Given your description, I suspect that you had a compass or IMU error which caused the irratic behaviour.
I've no idea where in your area you can get it repaired, but I suspect it could be a DIY repair, but as the
P4P has the avoidance sensors in the landing legs, it maybe more complex. Can I also suggest, Chris, that you spend some more time learning how these AC fly and, what you do and do
not need to do in terms of updates and, especially given what's happened today, how to fly
and control them in ATTI mode, so you learn what to do when things go wrong.