Version hacking in a nutshell:
v1 = No need to do anything extra.
v2 = Use root exploit, connect using your own ISP, download qnxflash and reflash. v3/v3b/v4 reflashing methods work too. You can also "degoop" the BIOS and replace it.
v3/v3b = Connect a hard drive with a v2 image and qnxflash on it. You can also "degoop" the BIOS and replace it.
v4 = Same as v3/v3b but you'll need qnxflash 1.02. Probably SHOULD NOT have BIOS "goo", you can just replace the chip if you're not up for the challenge of reflashing.
v5 = BIOS needs to be hotflashed or replaced, it's a good thing it's not glued in.
and now the versions:
v1 = Male voice in the interactive demo, root exploits work, BIOS is NOT glued down. Screen is made by Sharp, sound chip is the Yamaha and the CPU is the IDT Winchip. BIOS will boot ANY operating system.
v2 = Like v1 except the BIOS is now glued down and it will only boot the installed QNX.
v3 = Female voice in noninteractive demo, root exploits do not work. BIOS is glued down. Rest of the system is the same as v2.
v3b = A v3 with security torx screws holding the base on.
v4 = Like v3b but no more BIOS glue. Has a RISE pr266 CPU and a Hitachi screen.
v5 = Like v4 but now has a NEW BIOS that will not allow setup access and the audio chip is now an AD1881AD.
In terms overall hackability and bang for the buck, a v4 is what you want when buying an I-Opener.