HTC Desire HD was launched in late 2010. It was the first phone to use the 1GHz Qualcomm MSM8255 Scorpion CPU, utilizing lower power technology for extended battery life and improved performance. The 4.3″ WVGA TFT LCD is driven by the Adreno 205 GPU. At the time of its release, it ran on Android 2.2 Froyo.
HTC Desire HD is an ancient device but the development of this phone is still going. CM 12 ROM has been developed for this device and the 1GHz processor makes it possible for the device to handle the Lollipop OS. You can try it on your device. Follow the steps given below.