Can I unbrick my PSP wihout using pandora battery?

OK, I have a 3.71 m33-3 custom firmware and I am thinking of installing a higher firmware. Can I unbrick my psp by just using the m33 recovery menu and enabling usb connection and then set the read location to flasho and copy the flash0 files that are already on my computer? Would it work or would it fail miserably?

Well your PSP isn't bricked first of all, it just has CFW. You can revert back to OFW just by getting the upgrade and installing it normal by going to the eboot from your XMB. No pandora battery required. But if your PSP is bricked, you will require a pandora battery.