I believe cyanogen's recovery image has the capability as well. For that matter his ROM has the disk tools, only problem there is the fact that you need to have the partition unmounted during the process. Therefore my opinion is if you are really set on updating to EXT4, then get a bootable Linux CD.
OK thanks, I'll try that. I have latest Cyanogen, recovery 1.3.1, I don't have linux, but I have an Ubuntu 8.04 LiveCD, latest SPL and radio with ext3 and linux-swap on SD. Thanks again, I'll post back results.
XDA Developers was founded by developers, for developers. It is now a valuable resource for people who want to make the most of their mobile devices, from customizing the look and feel to adding new functionality. Are you a developer?