Might as well post this in this thread too.
Figured I'd write a guide based on my experience and what I've learned in the threads here. This is with a 1TB EVO and a 5.5. There are definitely options that present fewer difficulties, but this is for anyone who is using the same.
Tools needed:
5.5gen 80GB iPod Video
Samsung EVO 1TB mSATA
mSATA to ZIF adapter
mSATA to SATA adapter
Spudger
USB+Firewire Y-cable
iPod Firewire Adapter
A bit of stiff wire or similar to dislodge the battery latch
ice packs
Software needed:
iTunes
Rockbox
beyondwind's mSATA patch for Rockbox
1. Fully charge your iPod
2. Insert mSATA drive into mSATA to ZIF adapter
3. Use spudger to open iPod
4. Use a bit of wire to dislodge the battery connector. Be careful not to break it or you'll have to buy a new logic board!
5. Use spudger to lift the securing latch connecting the ZIF cable to the hard drive.
6. Remove the hard drive.
7. Connect the ZIF cable to the mSATA to ZIF adapter
8. Secure the latch.
9. Reinsert the battery cable and push the securing latch down with the spudger.
10. Close up the iPod
11. Connect the USB/Firewire y-cable to your iPod
12. Plug the Firewire end into the Firewire charger (with the charger plugged into an outlet).
13. Plug the USB end into your PC.
14. Run the iPod restore process in iTunes. Do not do anything until the iPod resets and iTunes displays 'Welcome to your new iPod'. This can take a while.
15. Close out iTunes.
16. Place an ice pack underneath the iPod.
17. Begin copying your music in 100GB sets with 15 minute waits in between. Replace the ice pack as necessary to keep the iPod cool.
18. Run the Rockbox utility and install the Rockbox firmware. DO NOT RESET THE IPOD!
19. Copy the .rockbox folder from beyondwind's mSATA patch over the existing folder on your iPod.
20. Safely eject the iPod and wait for it to reboot into Rockbox.
21. If you get the 'Dir buffer is full' error when you go into your music directory in Rockbox, increase the 'Max Entries in File Browser' setting under 'General Settings'. This requires a reboot to take effect.
22. I HIGHLY RECOMMEND disabling inactivity shutoff in Rockbox altogether and just making sure you charge frequently. Not doing this resulted in the iPod booting to 'Connect your iPod to iTunes to Restore...' after a few shutdowns.
The mSATA to SATA adapter is for when you inevitably screw up or let the battery drain too far and you end up with the 'sad face' on your iPod telling you to contact Apple support. When that happens,
1. Plug the mSATA drive into the adapter.
2. Connect the adapter to your motherboard.
3. Boot up a Linux live disc. (I use Mint)
4. Open terminal
5. Run 'sudo dd if=/dev/zero of=/dev/sdX bs=1024K count=1024' replacing sdX with the actual drive ID in Linux.
This will clear the MBR and allow the iPod to see the drive in disk mode again.