There are seven steps to pass the activation of T-Mobile G1 phone and you can follow all the steps only in 30 seconds. What you need is a blank SIM card and an activated T-Mobile SIM. Just follow the instruction below step by step, it’s easy.
1. Insert friends activated T-mobile SIM into G1 along with battery
2. Power on and wait for setup screen
3. Go through setup process to link any Gmail account
4. Go to Settings > Wireless Controls > Wi-Fi Settings > Enable Wi-Fi
5. Connect to nearby Wi-Fi network if one is available
6. Optional: Stop the phone from syncing with Gmail account by going to Data Synchronization and unchecking Auto-sync, Gmail, Calendar, and Contacts
7. Once done, take out friends SIM card and insert unactivated SIM that came with G1