how to crack MD5 middle with MASK attacking mode?

Hi Folks,

I'm cracking a MD5-middle hash of password "EfEVp5953R" using below command(MASK mode).
./hashcat-cli64.bin -a 3 -m 5100 hashes/1.txt EfEVp5953R

But it seems "M 5100" only works for "left half" not work for "middle half" and "last half".
More specific, if I put "40030674df2ef9d7" into hashes/1.txt, the password can be recovered; if I put "b1db24f7416abeee" or "df2ef9d7b1db24f7", it can not recovered.

Any switch/option to enable the middle/right MD5?

Thank you very much!

Jun

P.S.
MD5{EfEVp5953R}=40030674df2ef9d7b1db24f7416abeee