[Windows Phone 7 Development and Hacking] JulietteOnXDA:
Evening,

This a tutorial about how to easily downgrade your HTC Phones bootloader to install hspl and custom roms.

FAQ:

1) What is a GoldCard? A) It's a method to easily flash ROM files etc.

2) My phone performs an infinite reboot-loop, what to do? Answer: A couple of reboots are normal, if the phone keeps rebooting for more than 5 minutes, try this:

a)

Be sure to format the card to fat32

b)

Try another sd-card/flashdrive or a different card reader.

c)

Check your cable configuration.

3) Can I fix a bricked bootloader with this method? Answer: Yes! If you're able to get into USB-Host Mode it's possible. If you're not able to get into USB Host Mode with a bricked bootloader, post a comment with you're device details, we might be able to help you out.

4) Only shows "Entering USB Mode" Answer: This means your phone can't access the file. A) Try another cable configuration B) Check if card is formatted to fat32 C) try another cable, card reader or card.

Some cards/flash-drives just don't work.

I highly recommend to use a SD/MicroSD card, since they're way more likely to work.

What you need

Hardware:

- Micro SD Card or SD Card. Some users succeeded using flashdrives (for example USB-sticks), but I highly recommend SD Cards/MicroSD Cards., since most flashdrives don't work.

- Card reader

- Y-Cable USB

- USB Gender Changer

Files:

- Goldcard-tool

- My custom goldcard.img

- Your device-specific .nbh image.

You need to download a nodo rom for your device and extract Ruu_signed.nbh via Winrar. Rename it to

-Sparimg.nbh for Spark (Trophy)

Rom-download: http://xdaforums.com/showthread.php?t=1427904

-Spawimg.nbh for Verizon/CDMA Spark

Rom-download: http://xdaforums.com/showthread.php?t=1427904

-SCHUIMG.nbh for Schubert (HD 7)

Rom-download: http://xdaforums.com/showthread.php?t=1427890

-MOZAIMG.nbh for Mozart

Rom-download: http://xdaforums.com/showthread.php?t=1427893

- MONDIMG.nbh for Mondrian (HTC 7 Surround)

Rom-download: http://xdaforums.com/showthread.php?t=1427902

(Feel free to add more Devices in the comment section.)

or get a pregenerated package, ready to go: Many thanks to xda-user saywa!

So let's start:

Make sure you're battery is above 50%

Format the MicroSD Card to fat32

Copy the .nbh Image to the MicroSD Card

Launch Goldcard Tool

While ignoring the cid box, choose "Load GoldCard.img" and select the goldcard.img you just downloaded

Press "Patch MMC" and wait for confirmation

Unplug the MicroSD Card

Connect the Y-Cable and the USB-gender-changer like shown in the picture

Connect the MicroSD-Card

Connect your phone

Connect the y-cable to an ordinary usb port

Hold Power+Camera+VolumeDown until the USB Host Mode appears

Wait about 30 min until the update completes. The phone may reboot a couple of times.

After the update completed, unplug your phone and reboot

Now your spl should be downgraded.

Now you can install HSPL, visit this thread for further details: http://xdaforums.com/showthread.php?t=1195647

After that, you can install any custom roms. You'll find those in the Development section of your Device forum in XDA. For example for Tropy here: http://xdaforums.com/forumdisplay.php?f=812

How to flash a ROM: http://www.guidingtech.com/mobiles/flash-rom-htc-wp7-custom-roms-coming-soon/

Disclaimer:

Certainly I do not take responsibility for any possible damage caused.

Credits for research to

Kr3i0s http://xdaforums.com/showthread.php?t=1371073

sh4d0w86 http://xdaforums.com/showpost.php?p=21896081&postcount=286

xboxmod http://xdaforums.com/showthread.php?p=10176994

Nullstring http://xdaforums.com/showthread.php?t=1429318