For all STBs:
Programs/Scripts needs 755 or 777 (7 = Read/Write/Execute)
All other Files 644 or 666 (6=Read/Write)
Simple to do:
1 = execute
2 = write
4 = read
--------
+ add needed rights
755
+ = root
++ = user
+++ = world
755 means also: read/write/execute for root
user and world can read/execute but don't write
You're allways root on a STB, so only the first (left) setting has any effect