из папки "INSTALL" скопировал папку "seplugins" на карточку памяти в корень.
Прописал ms0:/seplugins/cwcheat/cwcheat.prx в game.txt
Потом выключил консоль. Зашел в рекавери.
В пункте "Plugins" активировал cwcheat.prx [GAME].

Q: whathever i try to load cwcheat it's menu doesn't come up. what's wrong?

A: it seems that if you have a slow memory stick the plugin support can't load your prxs
and cwcheat is more affected because it's a 100KB+ prx (so quite heavy).
ATM lexar and datel memory stick/devices seems to be affected by this definitely
and can't be used to load any prx.
Dark Alex fixed the problem only in 3.90m33-2 so if you are affected by this you
might want to do that update. Another solution, but which works only for isos seems
to be m33 no umd mode. A work around to this problem is flashing
cwcheat to flash in the kn folder and modify the pspbtcnf_pops.txt / pspbtcnf.txt / pspbtcnf.bin
file to load /kd/cwcheat.prx after $/kd/mediasync.prx
(be carefull that kd and kn can change depending on the firmware version so be carefull with this)