The default (Safe) keeps the entire programming session at 9600
baud, which is proven reliable across all platforms. The Fast
option switches the serial port to 115200 baud after the initial
handshake for faster transfers.
Fast mode has not been tested on all USB host controllers and
operating systems. If you experience transfer errors, fall back to
Safe mode. The 57600 baud switch is known to crash the radio
and is not offered as an option.
115200 baud for the binary transfer phase (~8 s for full dump).
After the 0M PROGRAM handshake at 9600 baud, the serial port
is switched to 115200 baud. A sync byte is read and discarded.
On exit the baud rate is restored.