I recently had some issues trying to get my phone back to manufacturers stock quality, so I decided I'd put together a guide for how to get your HTC Chacha back on a European Stock ROM!
WARNING: Leaving your phone plugged in during certain parts of this method can cause problems. Only plug the phone in when it needs to be, otherwise you may have to start over!
To complete this, you will need your phone to be fully charged, any cable than can connect your phone to your computer, and the files that I'm providing
First off, download the files that I have uploaded here: fastboot.zip
Extract it, preferrably to the root of your C drive. The less folders you have to navigate to get to it, the better.
Open the folder, and move of the files inside of the "EU RUU 1.3 Files" folder in to the fastboot folder.
Once you've done this, turn off the phone completely. Make sure that Fast boot in the phones power settings is unchecked. (This fast boot is completely unrelated to the fastboot program, but prevents you from booting in to HBOOT).
Hold down the "Volume Down" button and Power button together to boot the phone in to HBOOT. Once it's done checking for PH06img files, use the power button to select fastboot, then plug your phone in to the PC. It should change text on the screen from fastboot, to fastboot-usb.
Run cmd through your computer, and (if you placed the files where I suggested) type "cd C:\fastboot" (without quotes).
Next, type "fastboot flash system system.img". (If you're having trouble here, such as "Waiting for phone to respond", you may need to install HTC Sense)
Then, type "fastboot flash boot boot.img".
When that's done, type "fastboot flash recovery recovery.img".
Once that's finished, BEFORE YOU DO ANYTHING, REMOVE THE USB CABLE.
Once you've completed all these steps, your phone will be on Android 2.3.3, and EU Stock ROM 1.33. Before you reboot your phone, press power on "Bootloader" on your phone, then using the volume, select "Factory Reset". This will minimise any issues continuing with this guide.
Start up your phone, and skip through the set up. If you're not using a SIM card or don't have a data plan, make sure that you set up your WiFi during the set up. Open up your phones settings, go to About Phone, and then check for updates. This will update your phone to Android 2.3.5.
Once the update has downloaded and completed, leave the phone to reboot its self. If at this point, your WiFi is now showing "Error" when trying to connect, continue reading this guide.
If not, go ahead and run the updater again to update your ROM to the newest version (which at this point, is 1.54)
For those still reading, you have two options. If you have a data plan, use it to download the newest update. If you don't have a data plan, plug your phone in to the PC via USB, and select "Internet pass through".
Now, run the updater on the phone again, but don't install it yet! Once it's downloaded, look at the files on your phones Micro SD by connecting through your PC. Find "firmware.zip" (not 100% on the name), open it up, and copy across boot.img and recovery.img to your PC.
Delete the original 1.33 RUU files that you updated with, and place the new files you copied in to your fastboot folder. Unplug your phone
, turn it off completely, and boot back in to HBOOT, then in to fastboot.
Plug in your USB cable, run cmd and navigate to the fastboot folder again.
Now, type "fastboot flash boot boot.img", and then "fastboot flash recovery recovery.img".
Once this is complete, again, make sure you unplug your USB cable!
Now, you can reboot your phone.
Your WiFi still won't be working, but don't worry. Run the updater again (data plan, or internet pass through), and install it.
Once the phone is done installing the update, everything should be back to normal! Back to stock, and with all features working.
raymerjacque for creating the original "back to stock" guide
shipped-roms for hosting the original European RUU's
urzici for figuring out how to get WiFi/USB working again after updating