* Use dual LDO
* Add I2C EEPROM
* Update RESET switch
* Add bulk cap to STM VCC
* Add diode on debug VCC
* Add bead for sensor filter
* Use separate USART
* Remove power switch and its decoupling cap
* Resize the mounting holes to 2mm
* Connect the switch to NRST instead of BOOT0
* Change RGB LED footprint to PLCC-6
* Change switch footprint
* Add extra pads to usb connector
* Remove crystal and load caps, use ceramic resonator
* Replace single resistors with resistor networks.
* Add pull-ups to the uSD SPI signals and unused pins.
* Add a 2mm pitch debugging header.
* Breakout I2C3, SPI3 and USART3 using the main header.
* Fix silk screen component names.
* Connect the sensor's PWDWN and RESET to GPIO.
* Add a MOSFET load switch to enable/disable power to the uSD.
* Add a bulk cap to STM micro.
* Add a switch to enter the DFU mode.