After releasing his firmware dumper for the psp GO, neur0n is back with an update to his 6.60 ME & LME custom firmwares.
The v1.7 update to the ME & LME versions fixes a bug where the PSP would freeze if it entered sleep mode with the "Speed Up MS access" feature enabled and adds a "Text Color" option to the recovery menu. neur0n has also refactored the code in the firmware.
If you have 6.60 ME / LME already on your PSP, you can use the firmware's Network Update feature to update the firmware or manually update them using the files found on neuron's site. If not, then you will have to take the long way out.