go to this
website then download the Sony Reader System Update. Then extract the file into a folder(I did it with winrar).Then go to ebookupdater/assets/updaterAssets/ and open the PrsVersion.dat with notepad. Chang the number to another which is bigger than your currently version such as 150018040. Then connect your reader to pc and run the update. after running your reader will have the english operation
. I dit it with a german prs505