Just a quickie on this topic. Its very easy.
Tools Needed:
hex editor: https://mh-nexus.de/en/hxd/
PowerVR TexTool: https://community.imgtec.com/downloads/ ... k-2017-r1/
(its an online installer and you can select to only install the needed program to convert the files)
Got ur files? K Kewl...
First fire up the hex editor and delete these bytes of data in the pic
Before

After

Next after doing that. Just rename the file extension to .pvr

Once completed feel free to open in the program PVRTexTool

Have fun, and enjoy!

ps: Here are some necks from GH:L

GHL_Necks.zip
http://www16.zippyshare.com/v/EVmFtOdX/file.html