Yes!
Load GH1__132.bin into ptool, apply your patches, save a new firmware .bin (such as GH1__133.bin), copy it onto a camera-formatted SD card, put in the camera, press play button, then update firmware.
If you are new to using the patches, it's best to load one of lpowell's patch sets (such as the "40Mb reliable in-camera playback" patch,) and not alter any of the three first tick-boxes (they should all be ticked.)
After the update, the camera will display its firmware version as 0.0. This is normal. This allows you to re-patch with any of the old manufacturer's firmware versions.
