Hi Xi Ruoyao. I can ensure libstdc++-v3 in GCC source could build with AVR. In fact, I have my own local version of avr-gcc 12 with full libstdc++-v3 support on both my windows and Linux. I believe your build process is wrong. 如果你要的话,可以加QQ群1076846339 , 我发给你。 Sent from Mail<https://go.microsoft.com/fwlink/?LinkId=550986> for Windows