-a
--all
-
    Do not scan only the initialized and loaded sections of object files; scan the whole files.

[...]

-T bfdname
--target=bfdname
    Specify an object code format other than your system's default format. See Target Selection, for more information. 

[...]

-e encoding
--encoding=encoding
    Select the character encoding of the strings that are to be found. Useful for finding wide character strings. Possible values for encoding are:
`s' = single-7-bit-byte characters (ASCII, ISO 8859, etc., default),
`S' = single-8-bit-byte characters,
`b' = 16-bit bigendian,
`l' = 16-bit littleendian,
`B' = 32-bit bigendian,
`L' = 32-bit littleendian.