Cant get ESP8266 wifi modul respond to AT Command

It responds sometime with scrap letters and so on.. or it make nothing.. downloaded flash soft for de ESP8266 "v0.9.2.2 AT Firmware" and it got true... it sad "OK" to "AT" commands it write lots of scrap text. and it show sometime OK after AT command but mostly crap and its says something about bad checksum after update. and i try another firmware "At_firmware_bin1.54" it get worse.. but no bad checksum and no answer AT command only scrap text to Serial monitor.. in 115200 baud.
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