Recovering from report error #51 to TiVo

funtoupgrade said:

After restoring a new larger hard drive to each of my two TiVos I found that the TiVo software was indicating the unit was detecting a hardware error and that I should do a reset to clear the problem. The message also indicated that if the reset did not clear up the problem I should call TiVo and report error #51. Doing a search on this forum was no help with this error number (that I could find anyway). On my Humax the error message said to call Humax and report error #51. My first conclusion was that Time Warner did something to cause the problems, but before blaming them I decided to call TiVo as directed. I called and reported error #51 which the tech never heard of. After going though a number of hoops with him, we determined that the TiVo would not record in any mode. Since the hard drives were just installed I had not yet gotten that far in getting the units ready for normal use. After jumping through some more hoops he said the software was corrupted and I needed to do a clear and delete everything to return the unit to factory specs.

I have just completed doing this on the Humax and the error message is gone. The unit seems to record normally in manual mode which it would not do before, so the "clear and delete" seems to be the magic fix for this particular error message.

I will initiate the process on my series3 tonight before going to bed so it will be ready for the new guided setup in the morning. I am hoping this process will not screw up my cable cards which I just got working again after a power outage and several Time Warner visits.

Click to expand...

But that aside, heres the most accurate description of what is going on with the error #51 message. When your tivo first boots any hard disk that is in a virgin state (e.g. the tivo OS is loaded to the hard disk but it has never been booted before) what it does is generate a hash key that is seeded based on the serial number of your tivo and some random number, then it stores this information into the MFS database as a value labeled "DiskConfiguration" effectively marking that hard disk to be used in that *specific* tivo.

This key is used as part of the encrypt/decrypt process of your tivo whenever it records any video, and it effectively ties those video streams to your tivos mediaswitch asic so that theoretically you can't arbitrarily give your friends a copy of your recordings (note I say theoretically because we have long since defeated this measure.)

Now, when you take this hard drive and move it to a tivo with a different serial number (and thus presumably a different mediaswitch asic with different private keys,) the tivo will boot up and read the diskconfiguration key, and it will notice that the serial number seeded into that key doesn't match the serial number of the current tivo. Thus it bombs out and assumes that all of the videos currently stored on that hard disk wont be able to decrypt properly, thus it wont allow you to play any streams, and it also assumes that if it tries to record anything new, something else will go wrong as well.

Now that may or may not be the case, dependent on whether or not you recorded those shows unencrypted. Either way though it will turn your tivo into a doorstop, giving you that error #51 message until the situation is resolved. This is where 51killer.tcl comes in. What it does is simply erase the DiskConfiguration key from the MFS database. Thats it. It is really a very simple script. When you reboot your tivo, it'll notice that the diskconfiguration key is not there, so it will assume that the disk is in a virgin state (even though technically it isn't,) and it will then generate a new diskconfiguration key and then tie the hard disk to its current serial number, and all new CSO keys for the new recordings will be generated (or not, if you hacked tivoapp properly) based on that new key.

Note also that clear and delete everything does pretty much the same thing. C&DE clears out every value and every object that is not essential for the tivo to actually function - to include the diskconfiguration key. Thus when it reboots, you have the same effect, just like plainbill said. The whole purpose of 51killer.tcl is to be able to remove the error #51 message without being destructive to all of your recordings, settings, season passes, etc as opposed to what the C&DE does.

Now in your case, one of two things is going wrong here. Either you didn't actually do the C&DE (you probably selected the wrong option, it is the very bottom option that is specifically labeled "Clear and Delete Everything," as in it totally nukes all recordings, thumbs, season passes, etc.) or there is something wrong with your crypto chip (although this is quite doubtful.)

Click to expand...

unitron said:

Google "tivo error 51" and you'll find plenty to read.

Click to expand...

funtoupgrade said:

Sorry, I assumed all the important info regarding this problem would be somewhere on this forum and not elsewhere.

Click to expand...

funtoupgrade said:

Could someone elaborate on the "51killer.tcl script"? This does not mean anything to me, and I would love to know how to get/use it since a clear and delete does unpair the cable cards. In our area (Orange County CA) Time Warner refuses to let customers pair up the cable cards via phone and insists that a tech come out and do it on the phone - very dumb!

Click to expand...

mr.unnatural said:

The 51killer.tcl script is used on a hacked Tivo to remove the error #51 by clearing out the diskconfiguration key on your Tivo's hard drive which would otherwise prevent the recordings from playing back on the drive. The only other way to get rid of the error is by performing a Clear & Delete Everything which erases all recordings from the drive. The 51killer.tcl script allows you to transfer a drive from another Tivo of the same model without losing your recordings.

You may be able to find it via a Google search. If not you may have to go to the "other" Tivo forum that discusses Tivo hacks not addressed here.

Click to expand...

mr.unnatural said:

The PROM needs to be modified in order to break the "chain of trust" on the Tivo. Once you've done that you can modify the tivoapp file and install any other hacks you'd like. The main purpose of this is that when you hack the unit, your installed files will remain intact.

The Tivo performs a check during bootup to see if any files have been added or modified that differ from the ones that were originally installed with the OS. If it finds something that does not belong, it deletes the errant files and removes all of your hacks.

Hacking the Tivo byasses this startup check and allows any installed hacks to stay installed. The rc.sysinit file you create is run automatically and then initiates any installed hacks set to run in the background. One of the hacks involves setting up a bash prompt. This allows you to connect to the Tivo via a serial cable or telnet and run scripts from the bash prompt, such as the 51killer.tcl script. The 51killer.tcl script runs and clears out the mismatched data from the hard drive, as described in my previous post. When the Tivo reboots it rebuilds the data based on the current hardware and allows your existing recordings to play.

Click to expand...

stevel said:

No - you would have to have previously disabled encryption on the box that recorded the programs. As far as I know there is no way to remove encryption already there on that model TiVo. All 51killer.tcl gets you is avoiding recreating season passes, etc. The recordings will be there but will not play.

Click to expand...