Update: Dark_AleX is back with 4.01 M33 update #2. Download below.
Changes:

Nids resolver: Fixed scePowerGetCpuClockFrequency issue. This is the same bug that happened in 3.80 M33-1, it won’t happen again ¬¬
Fixes recovery problems that have apperared in prior version (incorrect position of back string in language others than english, enable, and disabled strings not translated in […]

The promised 1.50 kernel add-on for 4.01 M33 is here! This will allow you to run homebrew written for firmware 1.50.
Unfortunately, for PSP Slim users, this will only work with the original Phat PSP. To install, check the readme for instructions. In addition, you will need to download the official 1.50 firmware update, rename it […]