Change My Hostname ★ Root

Requires ROOT access

New permission used to set the host name after your device has been restarted, now it will maintain the host name you specified after power off and on. RECEIVE_BOOT_COMPLETED.

Changes your device host name on the network, so instead of having "android_AEF78f8e9d0h45" you can specify whatever name you want and it will stay that way even after you restart your device,

it does not work without root, please make sure you have rooted your device before

i will not provide instructions on how to root your phone, search google for help
http://www.addictivetips.com/mobile/how-to-root-your-android-phone-device/

Tested and working OK on Desire, Maybe your phone not Rooted, or where did you checked your Hostname after the change? some routers keep the hostname for some time after the change