To everyone having problems, did you flash gumbo 1.5c rom, or just the gumbo custom memory kernel?
If you just flashed the kernel are you running it on top of a different rom or just on top of the sprint rom?
Gumbo built support for setcpu right into his rom. It should automatically be booting up to 245/528 on demand automatically. Something makes me think that something went wrong with the flashing of his kernel. The custom memory killer kernel will not flash over the stock sprint rom. If you just rooted then flashed gk031 kernel, then it is doing nothing. I suggest checking out a rom with a SU whitelist built in already, such as fresh 1.1, or even better
gumbo 1.5c which already has the
memory killer set up. Setcpu will work great once you have done that.
If you have already flashed a rom and are still having problems, I have seen a few cases where people had faulty or corrupted SU whitelists causing problems like this.
Download a terminal emulator for your phone. (I recommend SUFBS). Get into the terminal, type SU, then type whoami. If your phone returns anything other then "unknown uid 0", you have a problem. Superuser whitelist needs to be reinstalled.
I have also seen a post floating around on the XDA developers thread where someone figured out how that you could flash the gumbo gk031 kernel on your stock sprint rom if you flashed an update.zip stripped from a modaco rom that included only the following items, SU whitelist, busybox. I would not recommend this if it was what you did, I initially had done that and was having problems with the version of busybox AND SU whitelist that was in the update. Broken symlinks and a corrupt file it seemed.
TL;DR Make sure usb debugging is enabled, if all else fails, wipe, flash a custom rom, flash the gk031 kernel if the rom you flashed doesn't already include it, then install SETCPU.
