How to and is it okay to update an iPhone Firmware finally

[OleOle]

I'm living somewhere where only Dialup is available thus I can't download large files. A friend of mine suggested that he'd download the iPhone firmware 2.1 for me and burn it into a CD so I would have it on my PC (He works for the government and they have a fast internet connection).

How to update the iPhone manually? Lets assume I had the file copied to my desktop, how do I then go about it? Also is it okay to do that or there might be issues with the phone?

Thanks in advance,

 

[ttech10]

I believe holding the Shift button while clicking "Check For Updates" allows you to choose a file. There shouldn't be any problems with doing it that way.