[Desire HD Q&A, Help & Troubleshooting] PauloMHAlmeida:
Before you do anything — Make a backup

Don't forget to back up your data. If you have synced the device with a Google account, then the contacts, calendar, Gmail, & select other Google-related data will not be lost and will come back after the next sync. However, you should backup anything you want to keep that is not stored on the SD card:

SMS/MMS messages,

Call Log,

Bookmarks,

Applications; use Titanium Backup or the Astro File Manager, for example,

Any application data not on the SD card.

It would also be a good idea to backup everything stored on the SD card in the rare case the SD card must be formatted to resolve any major problems.

MyBackup Root, SMS Backup & Restore, and Call Backup & Restore are all free applications that can assist with backing up your data.

Downgrade to an exploitable Firmware

AT&T Inspire 4G: Firmware Downgrade: Froyo, Gingerbread

HTC Desire HD: Firmware Downgrade: Froyo, Gingerbread

Rooting the HTC Ace

WARNING: ROOTING THE HTC ACE WILL VOID THE WARRANTY.

Before you begin, if VISIONary is installed on the HTC Ace, uninstall it before continuing.

You will need ADB on the computer to root the HTC Ace and to flash the necessary files for radio S-OFF. Follow the Android SDK guide, to get the ADB shell on the computer.

Download busybox, the ClockworkMod Recovery, the Engineering HBoot, gfree 0.7, psneuter, root_psn, Superuser package:

busybox: Download

md5: 25c5db694c987995909cc3166d4f01b0

ClockworkMod Recovery: Download

md5: 072a643b0aba983a4b9994db0e113c5e

Engineering HBoot: Download

md5: b2c8834905bfa2349f5223077493140a

gfree 0.9: Download

md5: 2dd45594b1ecb084401d428432f87010

psneuter: Download

md5: 89c2dec8d72d87b4c669f44dd31c8d17

root_psn: Download

md5: c8fe38ef55eb8951def9ff17b2eb99c1

Superuser package: Download

md5: 43d9a40b63e916635d5ad7ca32433fab

Unzip the zip files and copy the contents to the same folder as adb (the /platform-tools folder within the Android SDK folder).

Connect the HTC Ace to the computer via USB.

Make sure USB debugging is enabled on the HTC Ace by checking Settings » Applications » Development » USB debugging.

On the computer, open terminal and run the following commands:

adb push busybox /data/local/tmp/

adb push gfree /data/local/tmp/

adb push hboot-eng.img /data/local/tmp/

adb push psneuter /data/local/tmp/

adb push recovery-clockwork-5.0.2.3-ace.img /data/local/tmp/recovery.img

adb push root_psn /data/local/tmp/

adb push su /sdcard/

adb push Superuser.apk /sdcard/

adb shell

chmod 755 /data/local/tmp/*

/data/local/tmp/psneuter

NOTE: You will drop out of the shell after this command. Restart the shell using:

adb shell

cd /data/local/tmp

./gfree -f -b hboot-eng.img -y recovery.img

As it is very important that the hboot was installed correctly gfree calculates md5sums of the partition. It will calculate the following 3 checksums

md5sum #1 - checksum of partition 18 before the installation

md5sum #2 - checksum of the hboot image that should be installed

md5sum #3 - checksum of partition 18 after the installation

The messages that you what to see are either/or

md5sum #1 == md5sum #2 - the hboot image is already installed -> skipping installation

md5sum #3 == md5sum #2 - the hboot image was successfully installed -> OK!

If you get a different error message you should run for help at then DO NOT REBOOT and join #G2Root on Freenode for further help.

If gfree worked correctly continue with:

./root_psn

sync

reboot

The HTC Ace is now rooted with S-OFF, the Engineering HBoot & the ClockworkMod Recovery. Continue to the next section.

Flashing CyanogenMod

If the {{{device}}} has been rooted, unlocked, etc. through steps other than the method described above or running a custom ROM other than CyanogenMod and you are having issues flashing or booting CyanogenMod, it is recommended the {{{device}}} be returned to stock & start over with the full instructions provided above.

Method via Recovery

Download the [[Devices Overview#{{{device}}}|latest version]] of CyanogenMod.

Optional: Download the Google Apps for the device.

Place the CyanogenMod update.zip file on the root of the SD card.

Optional: Place the Google Apps .zip on the root of the SD card also.

Boot into the ClockworkMod Recovery.

Once the device boots into the ClockworkMod Recovery, use the side volume buttons to move around, and either the power button or the trackball to select.

Optional: Select backup and restore to create a backup of current installation on the {{{device}}}.

Select the option to Wipe data/factory reset.

Then select the option to Wipe cache partition.

Select Install zip from sdcard.

Select Choose zip from sdcard.

Select the CyanogenMod update.zip.

Optional: Install the Google Apps by performing steps 7 - 9 again and choosing the Google Apps update.zip.

Once the installation has finished, select +++++Go Back+++++ to get back to the main menu, and select the Reboot system now option. The {{{device}}} should now boot into CyanogenMod.

Method via ROM Manager

Launch RomManager.

Optional: Choose the first option in the app, Flash ClockworkMod Recovery to update to the latest version.

Select the Download ROM option from the main menu in the ROM Manager.

Select the CyanogenMod option, and then choose the latest version of CyanogenMod from the menu.

Optional: When you select the latest version of CyanogenMod, check the Google Apps option.

Once the ROM is finished downloading, it asks if you would like to Backup Existing ROM and Wipe Data and Cache.

If Superuser prompts for root permissions check to Remember and then Allow.

The {{{device}}} will now reboot into the recovery, wipe data and cache, and then install CyanogenMod. When it's finished installing it will reboot into CyanogenMod.

:crying:

I have try that was another fail lol...