Ti nspire hyperterminal problem

While i as installing cas on my nspire the boot2.img got corrupted .
Bought an usb ttl ftdi r323 cable and connetec to the pins 3-rx 4-tx 22-ground
Turn the nspire on pressing doc+enter+2 to flash new boot2 img but on hiperteminal i got a message og random things and the calculator dont stop sending it.
Any help on this???
Bought an usb ttl ftdi r323 cable and connetec to the pins 3-rx 4-tx 22-ground
Turn the nspire on pressing doc+enter+2 to flash new boot2 img but on hiperteminal i got a message og random things and the calculator dont stop sending it.
Any help on this???