Sorry for late bump, but did you ever get anywhere with this?
adb shell didn't work for me in recovery until i essentially pushed an entire /system/ partition in from a linux console. Required getting adb working in linux fiurst which isn't easy, but it's the only way you can set the execute permission... it work under virtualbox, so i'm happy to find the web pages which gave me the corect pointers...
unless you've alreayd fixed it of course
On another note, storage options finally got back to me with the helpful advice of returning my knackered pad for a new one...