Can't install HFW (No Applicable update data was found)

Hello.

I have a FAT model PS3 which is currently on OFW 8.43 and has never had any CFW on it. I'm trying to install HFW from a USB stick, but when I try to update the firmware, I receive the error "No Applicable update data was found".

The USB stick is formatted as FAT32. The stick is empty except for \PS3\UPDATE\PS3UPDAT.PUP
The md5 of the update file on the usb has been verified.

I'm using the right-most (closest to BD) USB port on the PS3.

Can you guys think of anything else to check...

Can't install HFW (No Applicable update data was found)