04-03-2019, 06:39
Hi,
For now, the first thing to verify is your AVR boards version.
Arduino IDE -> Tools -> Board: -> Boards Manager:
![[Image: ide187.jpg]](https://www.meteocercal.info/forum/images/01forum_img/misc/ide187.jpg)
Then check the Arduino AVR Boards version. If it is greater than 1.6.21, revert it back to v1.6.21 and program again both RX and TX boards.
If this not solve the problem, posting your Config_Options.h file may also help me to try to help you.
Thank you.
For now, the first thing to verify is your AVR boards version.
Arduino IDE -> Tools -> Board: -> Boards Manager:
![[Image: ide187.jpg]](https://www.meteocercal.info/forum/images/01forum_img/misc/ide187.jpg)
Then check the Arduino AVR Boards version. If it is greater than 1.6.21, revert it back to v1.6.21 and program again both RX and TX boards.
If this not solve the problem, posting your Config_Options.h file may also help me to try to help you.
Thank you.

