[Q] D6653 but can't work with LTE band 7,8

As you guys have known, D6653 should work with FD-LTE Bands 1, 3, 5, 7, 8, 28, TD-LTE Band 40.
When I flash the baseband (amss_fsg.sin,amss_fs_1.sin,amss_fs_2.sin) back from the stock rom, this is what the service info menu show.

So I change the NV Item value to enable band 7 and 8 which are my carrier support , I am still unable to receive the signal with my D6653 but able with the other phone.
Any idea?Thx