I know this is pretty self serving, but I keep seeing posts by people wanting to get this done and contemplating doing it themselves and this is something that should really not be attempted by someone that doesn't know what they are doing. It is very possible to render your TiVo totally worthless if you screw it up.
Unless you really know what you are doing with an iron, don't attempt it!
To remove the prom requires a special tip that can heat all pins on the prom at once so that it can be removed. Hot air can also be used to remove it. Last case is trying to use solder wick, but that would be very difficult to ensure all the solder is removed well enough that you don't damage the pads on the board when remove it.
Next the socket. Sockets in general are pretty hard, but PLCC (TiVO prom formfactor) sockets are much easier compared to TSOP sockets (xbox bios formfactor). There is still pretty much a requirement for a stereoscope or some other sort of magnification as the soldering is done on tiny points inside the socket itself and you have to be carefull not to bridge the legs or melt the pastic of the socket that is very close to the legs.
Flashing the prom also requires special equipment like a DATA I/O device that has PLCC sockets and is designed to flash chips. It may also be possible to flash the bios in motherboards that have a socketed PLCC bios chips in them. I have an ABIT BX2 that has this bios and socket, but I've not tried to flash non pc bios chips with it. I'm sure it's possible with the right software, I've just not looked for it.
If anyone is wanting to get this done, I have the facilities and the experience replacing and socketing the S2 TiVo proms. I can do both SA and DTiVo versions. Send me a PM if you are wanting to get it done, just don't screw up your TiVO cuz you don't know what you're doing.
UPDATE by alldeadhomiez, 7/24/2004:
KRavEN is no longer offering this service.
Sleeper and MudShark will socket and reflash your PROM for $50 plus shipping. Or, keep reading this thread to learn how to do it on your own.
At the time of this writing, the only model which needs a compromised PROM in order to boot a hacked drive is the HR10-250 (HD TiVo). It is suspected but not confirmed that the upcoming "silver" Series2 standalones may also require this modification.
UPDATE by JJBliss, 12/21/2004:
Sleeper is no longer a member of this Forum. Mudshark is, and has visited the forums recently. I am unaware if Mudshark is still doing PROM mods.
The HR10-250 no longer requires a modified PROM in order to boot modified software. killhdinitrd supports this unit as well as other non Series 2.5 units. Series 2.5 (nightlight and R10) units still require PROM socketing or modifications as of this writing.