I also can't get it to install.
In a moment of bad judgement I flashed the firmware and reset the device. Then I accidentally installed the Recent Files hack on the new firmware and got all kinds of weird behaviour, even after flashing again.
After some more flashing, I think it's working again (fingers crossed). But I can't install the new patch anymore. It simply doesn't do anything when I try to install. I can install version p4 but not p5.
Any ideas?
Edit: It seems I can't install anything anymore and this problem persists after firmware flashes, so probably not related to the latest patch. Too frustrated right now to look further into it though....