How to Flash ROMs Into a G1 Phone

Launched in October 2008, the G1 is the first Android-powered phone.

The Android operating system on phones like the HTC G1 can be changed or updated. These read-only memory type files, or ROMs, are saved into a section of flash memory on the device that's protected and reserved for the operating system alone. If you do not have root access to your phone's operating system, you cannot flash a custom ROM on your G1. Once you've obtained root access you can flash custom ROMs through the use of a small program known as a bootloader.

Things You'll Need

• Rooted G1
• Custom Bootloader

Instructions

1. Download a custom ROM for your G1. Several ROMs are available at code.google.com/p/android-roms. Also download a radio file and an SPL file. Connect your G1 to the computer and transfer the ROM, SPL and Radio files to the root directory of the SD card. Disconnect the phone from your computer once the files are successfully transferred.

2. Power off the phone and then hold the "Home" and "End" buttons to reboot into recovery mode. Choose "Flash Zip on SDCard" and then choose the .ZIP file for your Radio. Wait for the flash to complete. Select "Reboot System Now." It should reboot into recovery mode. If it doesn't, power off and then hold the "Home" and "End" buttons again to get back to the recovery console.

3. Choose "Flash Zip on SDCard" again, but this time select the SPL .ZIP file. Wait for it to complete and then reboot the system again. Return to recovery mode, and choose "Wipe." Then select "Wipe Data/Factory Reset" and let it delete all the data on the phone.

4. Click "Flash Zip on SDCard" one more time and choose the .ZIP for your custom ROM. Reboot the system once it's done and you will see your new ROM in just a few moments.

Tips & Warnings

• Once you've flashed a custom ROM, you can skip flashing the radio and SPL on subsequent ROM changes. Just load the ROM to the SD card, boot into recovery, wipe the data and flash the new ROM.

• You can render your phone completely inoperable with this process. Even if everything is done correctly, a data error at the wrong time could corrupt the files necessary to run your phone and it will not be recoverable. Proceed at your own risk.

References

• The Unlocker: How To: Load a Custom ROM on the HTC G1/Dream
• Talk Android: How To Flash Your T-Mobile G1 with custom Build ROMs

Resources

• The Unlocker: How To: Root the HTC G1 / Dream (AndRoot Method)
• The Unlocker: How To: Flash a Custom Recovery Image on the HTC G1 / Dream
• Google Code: Android ROMs Download List