To install the latest version of HSPL (now it is HardSPL4), all you have to do is close the HTC HD2, then hold the key to reduce volume (volume-down), and will press the power button continuously (key red / bottom right corner of the phone). Wait a few seconds (5 or 10), until You will see a screen with three colors and on white background is written: "Serial". Connect the USB cable from the phone to PC and you will see that on the white background will write "USB". The next step is to download and install it HSPL4 computer, to launch the executable
HSPL4.exeand follow the suggested steps. That's all!
What do HSPL4 knows?To install any version of SPL 1.42.0000, SPL 1.62.0000, SPL 1.66.0000, SPL 2.07.0000, SPL 2.08.0000, SPL 2.10.0000 and SPL 3.03.0000, you must have at least version 1.42.0000 installed in phone. Similarly, it is possible to downgrade to any older SPL version.
Other new features of HSPL4 is providing the possibility of flash any official ROM without using a Gold Card, all commands can be used for boot loader and it does not check NBH signatures, this meaning you can load any unofficial ROMs.