I remember some people came up with a way to install the 1.50 kernel on 3.73 HX-1, which didn't have an installer, so I'm going to look into that when I have the time. Until then, the only thing I use that doesn't work is PMP Mod (full 480x272 res video on PSP... the old-fashioned way!), but I can just use my other PSP for that.

__________________