I wish people would be specific. Is this an HDR or an HD?
IIRC the CF firmware-updating mechanism relies on you having a reasonably up-to-date firmware installed in the first place.
The package won't install if it's too old.
If rebooting your HDR-FOX gets you nowhere, you will have to resort to updating/re-installing firmware the old way.
Not necessarily...
I'm not sure whether you should also have installed the
cfupdater package first, or perhaps that was automatically installed as a dependency.
It's a dependency, like anything else that requires something to work.
Re-booted a couple of times and it came back!
Yes, it does. It seems it gets stuck in Maintenance Mode for whatever reason. Rebooting once or twice does an auto-clear of this and puts it back to normal mode.
The packages cfupdater and custom-firmware-hd ...
Ah, so it is an HD, not an HDR (unless you believe the thread title which says ...custom-firmware-hdr...). This is interesting because my HD failed in exactly the same way, so something's got broken along the way as it used to work.
I haven't had time to see what might be going on. As far as I know, the HDR units don't have this problem, as no-one has reported it.
I assume I would need to resort to the 'old way' so I'm inclined to leave it at that.
If you go back in to Maintenance Mode now, you should find a menu option to update the firmware (you need
tmenu version 1.25 installed, but it probably is if your packages are up to date).
Pick that and you should be presented with a choice (of 1 probably!) of which image to install. Pick that and it ought to install - it did for me.
Please report back success or failure.