the nokia update wiz should work with the 770.
It is probably the single easiest method (using windows) to flash the firmware for the 770 n800 and n810.
Of course the servers have been defunct.
Regardless it still works for flashing the firmware.
I have used it.... use it still...
Where you will find a copy nowadays?
I think papywizard still has a functioning link ...
though I have not checked it in some months now...
I would suggest if you cannot find it there (and really look please)
then I am sure in my n8x0 walkthrough I mention where it can be found.
I would suggest exhausting those options first.
Failing all that ..
(and I mean really failing ...I am purdy busy at this exact moment...)
...pm me.
But only in the direst circumstance when all hope is lost please...
frivolous pm-ing me (though normally very chatty ) ...
at the moment will not impress me.....
read the walkthrough I am sure it is there.

ach .... couldn't help it...
had to see...
here this page should help you ..especially in ref. to what to do...
I do know that if you wish the 2008 hacker edition (if mem. serves it wasn't quite finished and polished...vague fuzzy recall.) even the 2007 H.E. needed to be installed differently (I think .l remem. but don't quote me on my mind recalling 10 yr old data..)
The wiz wouldn't do for the H.E. versions I believe...
Standard official firmware can be installed easily with the wiz.though THAT I do remember...
This page should help...
read ..
read
read

http://www.kolor.com/wiki-en/action/...d_on_Nokia_770

Just finished reading... took me back to the good old days it did....
and I am quasi wrong... the 2007 HE should work with the wiz.
2008 HE is a different matter though. But it was half baked .... not finished... so 2008 HE is just something to putter with in my opinion...not meant for daily on the 770...too much was wonky with that version if I remember...