Sorry for the duff information, it's Flash 6 in the 770. The N800 started out with Flash 7, then got upgraded to Flash 9 in the latest firmware.

Correct, Flash is very much closed source. There is an open source project to reverse engineer Flash Player but it's nowhere near ready for prime time.

Unfortunately, the licence Nokia have with Adobe prevents any newer version of Flash being distributed on the 770 device. Apparently Nokia signed device specific licences with Adobe. And the same applies to Opera. Well, that's the story anyway, so no newer versions of Flash or Opera for 770.

OS 2007HE retained the same Flash and Opera versions from OS 2006, as luckily they both still work in OS 2007HE without any modification which would be impossible as Nokia don't have the source code etc. And due to the unofficial nature of OS 2007HE it would be very unlikely that Adobe and Opera would respin their code to ensure compatability with an unsupported firmware.