I have a HTC Touch Pro 2 smartphone. UK Release.
This phone was delivered with Windows Mobile 6.1 (WM6.1).
However already when I bought this phone, WM6.5 was available.
You can update this via the HTC website.
That’s fine.

But this is not what I wanted. Cause the ROM on the HTC website,
contains HTC Sense instead of Manila 2.6 (Touch Pro 3D – That
fancy swapping panels with your fingers.)
Actually there’s a whole community online, where developers create their own custom ROM’s. Means WM6.5 with Manila and pre-installed
Windows Mobile applications. (such as Twitter in your buttonbar).

I wanted to have a better ROM.
This one is more fancy and faster.
But you can not simply load a custom ROM on your device, it’s protected
by the manufacturer. And therefore you need a bootloader to flash your device.
This is called SPL. It stands for second program loader.
Basically there are two main types of SPLs. Hard and Soft.
There 2 times of SPLs: Hard & Soft.
A Hard SPL is one that is permanently flashed in your device memory and will boot up every time your device boots.
A Soft SPL is a stand alone .exe that is run on your device from within the OS. It basically changes your OS from running Windows, to initializing the boot loader.
Soft SPL is only loaded into RAM temporarily and will not survive a hard-reset.

Knowing these details I will guide you to flash your device
with hardSPL and a new WM6.5 ROM.
Note, that changing firmware and such is on your own risk:

1. Download the HardSPL package
2. Download the ROM you want on your device, for example: Miri. (based on official HTC Rhodium)
3. Save both files on your PC (not on a network drive), and make
   sure your virusscan or spyware blocker is off. –
   These scanners can complain about the exe files, but the files are trustfull.
   So it’s ok.
4. Run Rhodium-HardSPL_V2_00R3.exe, choose the first option (automatic flash)
5. Follow the instructions on your pc. Your device will have a black screen.
6. Then your device will reboot in the RGB colormode. – Note that the screen shows ‘0.85.OliNex’, which is the Hard-SPL version.
7. You can now load the ROM exe. Follow the instructions
   on screen. It will take a while, but then your device will be restarted
   with a new OS ROM and software!