In this pack you will find Flash_Loader, NandManager, and a customized CXMB
I have simply hex edited cxmb to have unique cxmb.prx, support folder and conf.txt so that each firmware loads the proper files it needs.
How this works
First, copy the contents of the zip file to your memorystick.
Next edit ms0:/seplugins/vsh.txt and delete the ms0:/cxmb/cxmb.prx 1 line or change 1 to 0 to disable loading cxmb from this seplugins folder because we will be loading this from flash0 at the end.
Now while in 5.00m33 run Flash Loader from game menu. This will modify psbtn files and add an seplugins folder to flash0 where we can have it load our plugins.
Now once back to xmb, enable flash0 via USB and edit the vsh.txt in seplugins folder to say
ms0:/cxmb/cxmb500.prx 1
This will enable the cxmb for 5.00 to load upon bootup and use the suppor5 and con5.txt file for loading ctf files.
Now when you reboot, your psp probably won't have a custom theme loaded because of the ctf name in con5.txt. So go to System - Themes - and pick a theme to make sure it works.
If it works


Good job..first half done...
Now install 5.50gen A then install gen B update.
If you payed attention to the first half of the procedures then you can probably figure out what needs to be done.
Now while in 5.50gen-b run Flash Loader from game menu. This will modify psbtn files and add an seplugins folder to flash0 where we can have it load our plugins.
Now once back to xmb, enable flash0 via USB and edit the vsh.txt in seplugins folder to say
ms0:/cxmb/cxmb550.prx 1
This will enable the cxmb for 5.50 to load upon bootup and use the support and conf.txt file for loading ctf files.
Now when you reboot, your psp probably won't have a custom theme loaded because of the ctf name in conf.txt. So go to System - Themes - and pick a theme to make sure it works.
Here's where it gets tricky...since cxmb lists ALL themes in the psp\theme folder, you will see both 5.00 and 5.50 themes...if you select a ctf for the wrong firmware, your psp will reboot and you will see the default xmb and probably say 'wtf SchmilK this didn't work' Well be smart and choose a 5.50 ctf or edit conf.txt and put in the name of the 5.50 theme you want to load.
If it works

Congratulations...now you can swap between firmware in under 2 minutes.
If you use ultimate vshmenu from total_noob, then you should disable it from the vsh.txt on memorystick and put it on flash0 in 5.00m33 because it WILL cause 5.50gen to crash.
That's about it. Hopefully this wasn't too confusing.
By: Schimilk
Download Dual CXMB: http://aab2c8d0.seriousfiles.com
Mirror1: http://a441edea.seriousfiles.com
Mirror: http://47ecee9f.seriousfiles.com