bold 9900 software

I have a friend who wants me to fix his bold 9900, as his is nuked (black screen, flashing red light), I did a bold 9930 before with the app loader and got it up and runnng. Now I just have a question with the app loader route I have to download the software and he just has a unlocked 9900 not the tmobile or AT&T one, should I just use the china unicom software from the link on the forums then? Also can anyone tell me where I can download older OS's incase I want to try and downgrade to fix it (I had to do that last time with the 9930)

thanks for your help