I had this problem this past weekend, when i tried to use InstantCake to upgrade a spare hard drive. The TiVo booted to the Welcome screen then went to a grey/white screen and froze. I read in the forums that it might help to format the drive to FAT32 first, problem, Windows wont let you format drives larger then 32GB in FAT32. This is when i turned to Google for help and found a program and instructions below. All I had to do was load the drive in windows and do a format to FAT32 with a 3rd party application, load InstantCake onto the drive and TADA! it worked. I hope this helps other people out there that have drives not formatted or formatted in NTFS.
(for use under Windows XP)
Click Start menu, select Run and enter diskmgmt.msc
If it asks you to initialize the disk, make sure you select a Basic disk, as opposed to a Dynamic.
There's a guide on Disk Management here You need to find the disk with unallocated space. Right click on it and select "New Partition" and follow these steps, clicking "Next" to get move on at each stage.
1. Partition Wizard starts, just click next to move on
2. Select Primary Partition.
3. Enter the maximum size for the Partition Size
4. Choose assign a drive letter. I used F:
5. Select "Do not Format this partition"
6. There will be a dialog box, summarizing all the previous stuff. Click Finish
Now you have a drive letter, this is what we will pass to the formatter
Now download a copy of fat32format. Extract the single EXE file to somewhere suitable, like C:\. Click Start->Run and enter cmd. CD to the where you extracted the fat32format exe file, e.g. by typing CD /D c:\
Now you're almost done.
You should see this displayed
Warning ALL data on drive 'f' will be lost irretrievably, are you sure (y/n)
Now when it says this, it really means it. If you format the boot sector, FATs and root directory will be filled with zeros. By typing pressing Y and hitting return, you're also absolving me of liability for whatever was on the disk before. ( So if you were using the disk before backup what was on it :P )
After this is done your drive is ready to be baked with InstantCake.
You should not have had to do this and from your description of the initial problem, my guess is that it was something completely different that caused your initial problem.
Most likely was/is a problem with your hard drive (did you run the manufacturer's diagnostics on it? If you didn't, there still could be a lurking problem that will bite you in the future) or could also have been a loose cable in your unit.
I'm moving your post over to the DIY software discussion area of the forum, but anyone who is considering this approach may want to first follow the instructions posted here (linked below) and best practices of running drive diagnostics, checking cables, etc before considering this.
Keep in mind that InstantCake has been available for about five years now, so we've seen all of the scenarios and again, see no reason to do *anything* with the partitioning/formatting of a drive prior to its use with the software.