1. EBOOT modified to run game from HDD/USB and signed with 4.x keys.
2. Get it on 4.x OFW using HDD swap (install it on CFW then pit that HDD in OFW PS3) or redirect PSN traffic to install .PKG from PC. (Can we sign .PKGs?). Or can the PS3 download .PKGs from the browser?
3. EBOOTs run on OFW.
I doubt this works since surely the Devs would've said it.