Changelog:
- Add upload bootloader speed menu option
- Urboot has automatic baud rate detection, so the upload baud rate can be changed without flashing a new bootloader binary. The Default baud rate option should always work for the selected clock speed. However, faster or slower baud rates may be used if the baud rate error is within about ±2.5%. Use a baud rate calculator to check whenever a clock speed supports a particular baud rate.