It seems poisonhzkj is hard at work on improving his homebrew. We just learned that he's released some new versions of his CXMB plugin, and it should now allow people to use it on 3.71 and 3.90 firmwares.

For those who haven't heard of CXMB, it's a custom firmware plugin that allows people to have an easier time at customizing their PSP's XMB. Best of all, poisonhzkj notes that CXMB doesn't write to flash, which means you have less to worry about.

As a final note, make sure you check the readme included in each download so you can learn how to install and use the plugin properly. That being said, have fun customizing your XMB!