Help! 13192sard does not goes to program mode

[alexanderister]

i loaded my program using serial bootloader in my sard and after that it does not switch to programm mode no manner how long i try to push all four buttons and reset. Please help.

[alexanderister]

OK, for now its clear what i have done. Somehow i could erase bootloader from my SARD microcontroller by loading my program through RS232. I dont know how could i do it and dont know how not to do this again but the problem could be sloved by using usb bdm only.