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View Full Version : Reversibility of hacking Prom?

Willy
11-18-2001, 01:55 PM
This is all great stuff. As I am building my serial cable now, I have one question concerning the prom hacks: Is there a way to restore your PROM to the original? Just in case of Murphy's law, it would be nice to be able to start from scratch to be able to successfully complete these modifications.

What I am asking I guess: is there a way to backup and restore the PROM, similar to the way you can backup and store images with MFSTools? Thanks.
_Formula
11-18-2001, 02:06 PM
The original PROM is a .bin in the /prom directory. For version 2.5 it's /prom/TiVoProm.ntsc.bin, or the link which is /prom/TiVoProm_2.05.bin on /dev/hda4. Just copy the file and that's your backup...
IWantMyDTV
11-18-2001, 02:31 PM
Willy,

If the prom burn goes bad, there is NO RECOVERY. Just want to make sure you are clear on that. A backup would do you no good, unless you could desolder the SMT prom from the board and replace it with a good one. (That or figure out a jtag connection for burning it.)

The TiVo uses the prom to boot. If the prom is bad it won't boot, and you cant restore a backup prom because of it.

Just FYI.
hwac
11-18-2001, 03:09 PM
i don't think the prom will go bad, if you can remove it you can reprogram it anytime. The chances of it going bad are rare these chips can take a beating

;)
Willy
11-18-2001, 03:18 PM
I realize the Prom burning is critical. Is there anyway to verify a PROM is good before the Update PROM command? I'm just a little paranoid I guess. The wife would be very upset if a fried PROM caused the demise of our Dtivo. Thanks.
T_RJ
11-18-2001, 03:35 PM
:D
Circuit city sells DTiVo for $99.00 for an additional $25.00 you get over the counter new prom.

:D T_RJ
Willy
11-18-2001, 04:20 PM
Good point...you're right. Luckily I already have this option...and away we go...
IWantMyDTV
11-18-2001, 05:32 PM
Originally posted by hwac
i don't think the prom will go bad, if you can remove it you can reprogram it anytime. The chances of it going bad are rare these chips can take a beating

;)

I guess I've been using the wrong terminology. When I refer to a bad burn, I take into account anything that could make it bad--including a successfull burn of bad code. :)