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[HOWTO] Downgrade Froyo (2.2) to Stock 2.1 (ANY HBOOT | WIN/LINUX/MAC | ROOT)

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teppic74
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Red face [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.

Update:
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.

Requirements

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
md5sum: f558a157e154e47331da67aa3c3d0a8b
[Downgrade utility (v2.1) - Alternate Link]
md5sum: 9b218e68068e77840d91c9d5edbf32ac

Process

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.

Further Information

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.

Linux/Mac Installation

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.

Windows Installation

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.

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teppic74
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Current version: 2.3

Known bugs:

Some newer phones may fail to downgrade properly with an error during the flashing process. If this happens, try installing one of the latest stock RUUs to recover.

Further Information

Backups

Downgrading requires a full factory reset, which is automatically performed as part of this process. There are various apps to help with backing up data from your phone. For example, 'SMS Backup & Restore' is a simple app that will back up your text messages to your sdcard and let you recover them later. You can back your contacts up using the People app (menu, and then 'export to SD card').

Recovery from broken screen

If you have previously run an RUU or tried an older downgrade method and your SLCD phone's screen is now disabled, the easiest way to recover is to run the official froyo RUU to upgrade. You can then either stick with official froyo, or downgrade to a working Android 2.1 release using this tool.

Other HBOOT?

You do not need a lower version, and installing a lower one will break SLCD phones. See this thread for information about this.

Reporting problems

Please include as much detail as you can, with at the very least any errors given by the utility. Also include the CID provided by the utility.

Changelog

2.3 - 05/09/2010
Fix testing bug in Linux/Mac version.
No changes to Windows version.

2.2 - 02/09/2010
Add OS X support.
Explicitly use bash (Mac compatibility)
Check for root on Linux/Mac

2.1 - 01/09/2010
New: goldcard requirement check.
Wait on phone instead of check for phone.
Move all file checks to phone.
Cleanup files on completion.

2.0 - 30/08/2010
Major reworking.
CID/misc partition handled automatically.
Verify misc partition image and downgrade image after transfer.
Check root access improved.
Various clean-ups.

1.3 - 30/08/2010
Linux: integrate misc partition image creator.
Sync transfers for extra reliability.
Use old-style sdcard location for Android 2.1 compatibility.
Various minor changes.

1.2 - 29/08/2010
Fix mtd0 backup error.
Backup mtd0 to sdcard instead.
New: Windows get-cid script.

1.1 - 29/08/2010
Windows script checks for PB99IMG.zip
Checks if the phone is already running a rooted ROM. If it is, the downgrade can now safely be performed.
Creates a backup of the existing misc partition.

1.0: Initial public version - 29/08/2010

Testing Status

No known problems. Tested on several ROMs included stock unbranded Froyo (2.09.x, 2.10.x) and O2 and Vodafone branded Froyo.


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hkfriends
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Great!, I think it also working for hboot 0.93... thanks
 
duttythroy
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(Last edited by duttythroy; 29th August 2010 at 01:54 PM.)
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[QUOTE=teppic74;7896742]CURRENTLY TESTING



My device screen is black so I cant get into usb to activate usb debugging any other work arounds been trying everything since yesterday

http://forum.xda-developers.com/showthread.php?t=767795
[Duttys™ HD2 Multi-Lang 23163 Legacy Cont. ROMs]
http://fileserve.com/list/dARfvDN

[Duttys™ HD2 Multi-Lang Legacy ROMs + Legacy Kitchen 23162 COOK Your ROM]
http://fileserve.com/list/HPbXnV3

 
teppic74
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(Last edited by teppic74; 29th August 2010 at 01:51 PM.)
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If your screen is broken already, just upgrade to stock froyo to fix it, then use this utility to downgrade.

The froyo RUU is here (goldcard required for branded phones):

http://shipped-roms.com/shipped/Brav...022_signed.exe

PS. please don't quote the entire first post (I will need to update it)
 
igor7
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(Last edited by igor7; 29th August 2010 at 02:08 PM.)
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So, if I have froyo 2.2 and hboot 0.92(slcd) I can receive 2.1 version without go trough step with black screen (like in tutorial for rooting hboot 0.92 on SLCD screen)?
 
duttythroy
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Quote:
Originally Posted by teppic74 View Post
If your screen is broken already, just upgrade to stock froyo to fix it, then use this utility to downgrade.

The froyo RUU is here (goldcard required for branded phones):

http://shipped-roms.com/shipped/Brav...022_signed.exe

PS. please don't quote the entire first post (I will need to update it)
ok I will try sorry about the quote fix it
[Duttys™ HD2 Multi-Lang 23163 Legacy Cont. ROMs]
http://fileserve.com/list/dARfvDN

[Duttys™ HD2 Multi-Lang Legacy ROMs + Legacy Kitchen 23162 COOK Your ROM]
http://fileserve.com/list/HPbXnV3

 
duttythroy
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Quote:
Originally Posted by teppic74 View Post
If your screen is broken already, just upgrade to stock froyo to fix it, then use this utility to downgrade.

The froyo RUU is here (goldcard required for branded phones):

http://shipped-roms.com/shipped/Brav...022_signed.exe

PS. please don't quote the entire first post (I will need to update it)
The problem is I tried this also, but My bootloader wont flash any rom from computer, the .exe can I just change it to .zip and rename to PB99IMG and use gold card
[Duttys™ HD2 Multi-Lang 23163 Legacy Cont. ROMs]
http://fileserve.com/list/dARfvDN

[Duttys™ HD2 Multi-Lang Legacy ROMs + Legacy Kitchen 23162 COOK Your ROM]
http://fileserve.com/list/HPbXnV3

 
teppic74
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Quote:
Originally Posted by duttythroy View Post
The problem is I tried this also, but My bootloader wont flash any rom from computer, the .exe can I just change it to .zip and rename to PB99IMG and use gold card
No - that won't work. The RUU exe should work on your phone unless there's a driver issue (common in Windows 7 x64). I think that sometimes uninstalling HTC Sync but leaving the driver present can help.
 
duttythroy
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Quote:
Originally Posted by teppic74 View Post
No - that won't work. The RUU exe should work on your phone unless there's a driver issue (common in Windows 7 x64). I think that sometimes uninstalling HTC Sync but leaving the driver present can help.
yes its strange I will try another computer its also windows 7 though, but somehow I cant get into bootloader or flash any ruu, and this black screen is killing me
[Duttys™ HD2 Multi-Lang 23163 Legacy Cont. ROMs]
http://fileserve.com/list/dARfvDN

[Duttys™ HD2 Multi-Lang Legacy ROMs + Legacy Kitchen 23162 COOK Your ROM]
http://fileserve.com/list/HPbXnV3


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