I can't build ZephyrRTOS with arm-none-eabi-nano-toolchain, because libc_nano.a is required by ZephyrRTOS when I enabled newlib nano config. Then I found there's only libc_nano.a in newlib-nano path, only libc.a. I think libc.a is for newlib, and libc_nano.a is for newlib-nano. Best regards. -- GNU Powered it GPL Protected it GOD Blessed it HFG - NalaGinrut Fingerprint F53B 4C56 95B5 E4D5 6093 4324 8469 6772 846A 0058