I do recall it being tricky to get them to work. Here's the info I grabbed from various places at the time:
Kickstart 57 – TiVo Diagnostics:
7. While the system is restarting, during the initial screen, press and hold the PAUSE button until only yellow light(s) illuminate.
8. Release the pause button and immediately type in the numbers 5 and 7 on the remote (you have about 10 seconds to do this step).
9. TiVo will reboot and the GSOD screen will come on saying TiVo has encountered a serious error. It will then run the disk management tool. During this time it will look for and correct configuration problems as well as isolating any bad sectors on the hard drive so they can no longer be used.
10. TiVo will automatically reboot after the diagnostic program has completed. This may take a few minutes to a few hours.
"Kickstart 58" is another of TiVo’s diagnostic programs. It runs fsfix with an additional option that causes it to make multiple passes over the inodes, re-hashing them and clearing collision bits.
Kickstart 58- TiVo Diagnostics:
7. While the system is restarting, during the initial screen, press and hold the PAUSE button until only the yellow light(s) illuminates.
8. Release the pause button and immediately type in the numbers 5 and 8 on the remote (you have about 10 seconds to do this step).
9. Put the remote down and wait. The system will proceed to the diagnostic program.
10. TiVo will reboot after the diagnostic program has completed. This may take a few minutes to a few hours.
“Kickstart 52” is an "emergency reinstall" of the software. It will reinstall the existing software on the alternate root partition.
Kickstart 52 – Reinstalling TiVo Software:
7. While the system is restarting, during the initial screen, press and hold the PAUSE button until only the yellow light(s) illuminates.
8. Release the pause button and immediately type in the numbers 5 and 2 on the remote (you have about 10 seconds to do this step).
9. After a time (generally a few minutes) TiVo will automatically reboot.
Kickstart procedures generally leave Season Passes, Wish Lists, etc. intact, however data and recordings that used any bad sectors may be lost.
Kickstart code 5 1 - software upgrade
Kickstart code 5 2 - emergency reinstall
Kickstart code 5 3 - BER testing
Kickstart code 5 4 - HDD test
Kickstart code 5 5 - Tuner/AFT test
Kickstart code 5 6 - software install
Kickstart code 5 7 - force MFS check
Kickstart code 5 8 - perform MFS cleanup
Kickstart code 6 2 - initialize E-SATA drive - S3 only
kickstart
While booting the power light will change from green to yellow as the line 'checkpanic' in the rc.sysinit gets executed. This happens a few seconds before the screen changes from the startup image to "almost there" and it's your cue to hold down a button (use pause) on the remote to trigger a panic. When the record light changes yellow, key in one of the following sequences:
0 - emergency call to tivo, touchtone dialing
1 - emergency call to tivo, pulse dialing
9 - emergency call to tivo, touchtone w/ 9 prefix
-- I suggest not doing any of these unless explicitly instructed
52 - emergency reinstall
-- this will act like you've received new software but will reinstall the existing software on the alternate root partition and boot it, particularly useful so you don't have to go trolling for backup images when your hacks fail.
56 - software install
57 - mfs check
58 - perform mfs cleanup
-- both of these will cause the green screen and various mfs checks