We have seen this many times with our MSA's. This is an issue with the older firmware. It seems the OS gets corrupted.
Unfortunately, we have not found a way to recover the controller, as you cannot login by any means.
We have always had to get a replacement controller from HP. Then once the controller is installed and synced to the active controllers FW, we immediately upgrade to a GL250 FW version to avoid this from happening again.
I am curious if using the 3.5mm COM ports (service only ports) there may be a secret way to recover, but we have not tried this yet.