Here’s how i get there, terribly straightforward. btw, i’m already on iPhone OS 3.0 beta 1 before upgrade.
2. Launch iTunes(i’m on 8.1), Shift+Restore to choose the firmware(iPhone1,1_3.0_7A259g_Restore.ipsw) to update.
3. After done, start quickpwn.exe to jailbreak and activate. No unlock necessarily ‘coz the restore process won’t touch the baseband.
4. Sync back all of your stuff by iTunes. In my case, I always set it up as a new phone ‘coz doing so makes me feel it’s a like brand new one 🙂
Enjoy the beta 2 now.