I've never used extended partitions before. I installed ubuntu 9.10 yesterday, and found out about grub2. I don't have a problem with grub "legacy" and would prefer to stick with it for a while. However, it won't load an ext4 partition, so I had to chain load ubuntu's grub2 with it as per this thread:
Today, before I get to into "kosmic koala" too far, I decided I wanted to leave one more partition on the drive, and since ubuntu doesn't seem to mind being installed on an extended partition, that's what I did (reinstall it there).
Now, the chainloading don't work. According to the grub docs, it will boot an extended partition. However, I get "Invalid device" (yes, I tried a few different numbers). Perhaps this does not apply to "rootnoverify", which is needed to chainload?
Hopefully someone out there has done this before -- otherwise I may have to get used to grub2...GRRR