Before the HTC Maple class can be flashed to a custom firmware, the Hard SPL need to be installed. However you can check the SPL version by holding [Volume Down] and doing a cold boot. Mine says 1.24. But I found a way to flash the Hard SPL down to 1.19.
Below are the original instructions:
1. Removed SIM and SD card
2. Connected, established a sync connection w/ActiveSync
3. In JockyW's folder; open "SSPL"
4. Run SSPL.bat
5. If you have a firewall or anti-rootkit running ie. COMODO Internet Security, disable those and the sandbox if your security software has one. I left Bullguard on.
6. Follow commands in command prompt
7. Pop up should show on your device's screen. You may need to dismiss those messages about no SIM cards etc first.
8. The "OK" option is outside of the screen's viewable area, press the trackball or press enter.
9. The phone's screen will shut off but the keyboard will remain lit
10. DO NOT DISCONNECT (Yes, I know there is nothing on the screen)
11. LEAVE ACTIVESYNC ALONE
12. Return to the JockyW folder
13. Run the ROMUpdateUtility
14. It will complete HOWEVER when you start your device, it will stay at the T-Mobile splash screen, but that's okay, given that your device should now be hardSPL'd and you are ready to get a new ROM to install and enjoy, because we know just how much the OEM ROM sucked. For me, the T-Mobile did not turn up.
You need to download the Hard SPL from xda-developer via: