Last night my A1200 with OS3.5 (yea - broke down and bought a MoBo from Airy on ebay) started getting the dreaded checksum errors on my WORK partition and then Intuition had a fit and couldn't load the desktop till canceling error. Then the WORK partition became invalidated.... the partition wouldn't auto-validate so I quick formatted it. Rebooted and all was well with booting the SYS partition. I started copying my WORK folders back from PCMCIA drive and the drive hung up middle thru copying the last folder - my WHDLoad folder. Had to turn off the A1200. BAM!
Now the CF card won't boot and both partitions are not auto-recognized in HDToolBox.
The symptoms you describe point to a dying CF card. You should not try to repair it, it will only die further. Put it into an USB card reader, connect it to a Windows PC and use WinUAE, dd, DiskImage or whatever to create a full backup image of it. Then use the image in WinUAE to salvage the data. Do not write to the card any more.
I know my old partition sizes but not the EXACT size of SYS. If I am close, do you think SYS will boot?
No, partition sizes must match exactly. However, if you know exactly where Work started, then SYS will most likely fill the entire space before it.
If I save the changes to the drive and it still won't boot, can I try to resize the SYS partition again defining a slightly different size? Or does saving a new partition destroy the data?
Yes. But as mentioned above, writing to the card will most likely cause more damage to the data.
But this is not necessary. There are programs which can investigate the exact partition sizes automatically. For example:
http://thomas-rapp.homepage.t-online.de/downloads/rdbrecov.lha
