Some people seem to be unaware that Cintro's are back. And yes you can use it on 3.90m33. Here is a step by step tutorial on how to use it.

                     Things you need

1. This will only work on a Phat PSP with 3.90CFW.(M33)
2. You must have the 150.pbp Get it here 150.rar
Once it's downloaded extract it and put it in the root of your MS.
3. Now you need the 1.50 v2 addon Get it here: 150k_addon390v2.rar Put it into your ms/psp/game folder and run it.
4. Now you need the seplugins get it here: seplugins.rar Put it in the root of your MS. If you have a seplugin with the vsh.txt don't copy the vsh.txt just add the line ms0:/seplugins/pmf_boot.prx to your existing vsh.txt file. Now shut off your PSP and go into Recovery and enable the mpf_boot.prx [vsh]. Exit recovery and your cintro should play.

Hope this is a help for those who are have problems getting it to work.
Source: YouTube