1、PC端 https://github.com/cidadao/efm32_loader
http://theramblingness.com/2015/07/16/a-gui-and-cli-utility-for-efm32s-uart-bootloader/
support for USB and uart bootloader,run in CLI or GUI mode.
2、MCU端 http://www.silabs.com/Support%20Documents/TechnicalDocs/AN0003.pdf
https://files.cnblogs.com/files/dong1/AN0003SW.zip
---------------------------------------------------------------------------------------------------------------------------------------------------------------------------
3、串口通过 YMODEM 协议进行文件传输