sim900A dosent work after update

[dizgah]

hi dear friends
i have sim900a worked fine,i need NTP & flash & midi applications that dose not support my last frimware,therefor i give latest frimware with this functions from simcom support & download its frimware.
module's frimware update succesfully but after it ,it dosent work
when i turn it on only a few weird character send (fewer than usuall ) i test all baudrate ,& even try to change baudrate but it dosnt work.
has any body any suggestion?
best regards