By having a PSP 1000, its a Fat PSP. and yes by running the custom firmware you should have the "6.61 PRO-C" on system settings, however, that's not the latest firmware available.
I Uploaded the last version of the custom firmware, just make sure your psp it son 6.61 and your model its the psp 1000 before applying:
Here is the Latest Version of the Custom Firmware: http://s000.tinyupload.com/index.php?del_id=60733690162347561276
And here is the Latest Version of the Permanent Patch: http://s000.tinyupload.com/index.php?file_id=00372569352924135627
To set it up, Run first the Custom Firmware Installer, and Uninstaller your current custom firmware.
Run the installer again in order to install the new firmware. which is 6.61 Pro C2.
then lastly run the Permanent Patch to make it permanent.
After that, you can just format your Memory Stick via System settings, and it will create every folder you need, just place your .iso games inside the ISO folder. make sure they are .ISO or .CSO
Hi my psp is showing the same thing my system setting is showing 6.61