Unfortunately I learned the hard way that you're not supposed to update the firmware from service mode.
The system is a fat 20g (with bigger hard drive), 3.41 and it had been working fine. I tried to update within the service menu, it rebooted and started installing the firmware but then went to a red screen in a whole bunch of languages saying there is a serious error.
What I THINK happened is that the PS3 copied the firmware to the hard drive, restarted, erased the firmware, and had an error when it tried to update. Now it doesn't have a proper firmware so I have a ton of problems.
-I can't get into recovery menu. Ever.
-It doesn't try to read/boot off the USB. I've tried using the "jig" files to get back into service mode, I've tried both self files and a bunch of firmware files (3.15, 3.41 factory, 3.41 modded, 3.50) the problem doesn't seem to be the firmware file as it does the same thing every time.
-If hard drive is installed that was in at the time the problem happened, the system starts, tries to update the firmware (0%) then goes to the red screen. This happens no matter if the jig or the flash drive with the pup/self files is in. (The LED does light up on the jig as if it was working but it makes no difference)
With no hard drive installed or another hard drive from another 3.41 PS3, the system starts and then shuts off after a minute or so. Due to ^^^this^^^^
I'm thinking the only way out of this mess is to somehow modify the hard drive that IS trying to update the firmware with a different file. 3.41, 3.41 modded... unless there's an alternate way to force update firmware?
Any help would be appreciated - i've tried tons of things and don't know where to go next.