From ModMyGPhone Wiki
This guide works for RC8 and Dev Phone 1 as well.
RC33 is US firmware, RC8 is UK specific firmware, both are interchangeable.
Requirements:
1. Download AndroidMod.zip.
2. Download JFv1.42 RC33 or JFv1.41 RC8. If you do not know which one to get, read this.
3. I recommend using ADB, but if you'd prefer to use telnet, unplug your usb cable (the one attached to your pc; if your G1 is plugged in to the wall charger, that can stay)
Note: Dev Phone 1 users should just download JFv1.42 RC33/ JFv1.41 RC8 zip and do the update, no need to flash the recovery.img file, you can skip those steps.
Steps ::
1. Rename the RC33/RC8 zip archive to update and copy it to the root directory of your MicroSD Card.
2. Extract the recovery_testkeys.img file from AndroidMod.zip to:
- if you are using ADB, extract it to the SAME directory ADB.exe and AdbWinApi.dll are in.
- if you are using telnet, extract it to your root directory of your MicroSD card.
3. In this step, we will copy recovery_testkeys.img to /data/local/recovery.img.
- if you are using ADB, open up a command prompt (Start > Run > cmd [then press Enter]) and type in
adb push recovery_testkeys.img /data/local/recovery.img
- if you are using telnet, extract it to your root directory of your MicroSD card.
Note: The commands below have to be entered through the adb shell if you are using that or through telnet on your computer.
Make sure you mount /system as read/write before proceeding,
mount -o rw,remount -t yaffs2 /dev/block/mtdblock3 /system
2. Copy the img file from SD Card or /data/local to /system
If you used adb do,
cd /system
cat /data/local/recovery.img > recovery.img
or if you copied the img file to sd card then do,
cd /system
cat /sdcard/recovery_testkeys.img > recovery.img
3. And finally flash the image,
flash_image recovery recovery.img
Turn off the phone and start into recovery mode by pressing and holding HOME + POWER button while booting. Once in recovery mode( exclamation mark..), press ALT+L and check if you see Using test keys, if yes then the flash was successful.
The hard part is over. Now press ALT + S to do the update. It will take a while, so relax. Once completed, phone will reboot couple of times then startup normally.
Thats it !
This guide borrows from the content posted here and here.
