[HOWTO] Downgrade Froyo (2.2) to Stock 2.1 (ANY HBOOT | WIN/LINUX/MAC | ROOT)
*Please note: this utility may not function with some very new froyo releases (e.g. the ARA release) and almost certainly will not work on the official gingerbread release*
This utility will quickly, safely and easily downgrade froyo to stock Android 2.1 (HTC software version 1.21.405.2, radio 32.41.00.32U_4.08.00.09, hboot 0.83), which can then be rooted with unrevoked3
. The downgraded ROM is fully compatible with SLCD and AMOLED screens.
You do not have to downgrade to Android 2.1 with the supplied stock ROM. After the process is completed, just cancel the flash and install the ROM you require using the standard RUU method (this utility will prevent the version error you normally get when trying to install an older release).
In other words, some typical uses:
- You have installed an update and want to revert to an older version.
- You have rooted your phone and want to return it to stock (e.g. for warranty or selling).
- You want to debrand your phone, or you have debranded and want to re-brand it.
It runs in Linux, Mac OS X and Windows. Please post your results, even if successful and without any problems. If unsuccessful please post the output from the utility and include which version your phone was currently on (e.g. 2.09.405.8 / hboot 0.92) and the CID that the utility gives you (e.g. HTC__001). If the utility reports that it has failed to root your phone, no harm will be done so long as you stop the process.
Newer versions of unrevoked3 (from 3.21) can now root froyo ROMs directly, and a downgrade is no longer necessary if you just want to root and install custom recovery, although there appear to be a few issues. If you want to rebrand/debrand your phone, rooting won't achieve this and you can use this method instead. If you cannot get the new version of unrevoked3 to work you can also run this and use the older version (3.14) that works with Android 2.1.
A working goldcard
if your phone is or was branded.
At least 150mb free on your sdcard/goldcard, formatted as FAT32.
Downgrade Utility (v2.3)
- Alternate Link
[Downgrade utility (v2.1)
- Alternate Link]
Previous froyo downgrade options are not really adequate for these reasons:
- They result in a broken screen on SLCD phones.
- They do not run at all on software versions higher than 2.09.405.8.
- They involve manually copying files and manual post-downgrade steps.
This downgrade has none of these problems, and will work on SLCD and AMOLED phones and any version of HBOOT.
The process is simple and requires minimal intervention - just a couple of key presses. A few reboots will take place as it flashes the downgrade, and this is nothing to worry about.
You can run this utility on Android 2.1 too. If your phone is rooted or has a custom ROM, it will be restored to a stock unrooted ROM.
This downgrade is not suitable for CDMA phones.
If you want to flash an alternative RUU (e.g. a branded 2.1 release), just skip the downgrade section at the end by pressing vol-down on the phone when the utility has completed. Then reboot the phone and run the RUU you want. If you have an SLCD screen you should be very careful here - most older RUUs don't support the screen.
If you want to run a custom ROM you need to apply the downgrade, and then root the phone using unrevoked3.
On some sdcards the phone might not detect the downgrade file (this is nothing to do with this utility, and it will not harm your phone). If this happens, trying a different card or re-formatting it as FAT32 will probably fix it. Otherwise you can install the same downgrade image directly using this RUU
. Note that you can only apply this RUU after running the utility, and it is only necessary if the phone does not detect the downgrade at the final stage.
1. Download and extract the utility in a terminal:
$ unzip downgrade23.zip
$ cd desire_downgrade
2. Enable USB debugging on your phone. Ensure 'ask me' is set under 'Connect to PC' setting, and 'charge only'. Plug in your phone.
3. Run the utility.
$ sudo ./downgrade.sh
4. Wait for the process to complete.
If you chose not to downgrade, you can now flash any RUU.
0. Install HTC Sync (driver required).
1. Extract the downloaded zip file fully (do not just click on the zip file).
2. Enable USB debugging on your phone. Ensure 'ask me' is set under 'Connect to PC' setting with 'charge only'. Plug in your phone.
3. Double-click on the win-down file.
4. Follow instructions and wait.
Notes - Please Read
You should remove the PB99IMG.zip file from your sdcard after completing.
This process will wipe all the data from your phone (except the sdcard).
The downgrade will work on branded phones only if a goldcard is inserted (without one: CID error).
The process will flash your recovery partition back to stock.
The downgrade installs an official (unbranded and unrooted) stock HTC ROM.
The downgrade does not depend on any version of HBOOT.
If the bootloader cannot find the PB99IMG file, try formatting the sdcard as FAT32 and try again.
Thanks: 743C (7-4-3-C@web.de) for local root exploit.
If this has helped you, maybe buy me a beer?