Hi, I have the same problem. Segger v7.32 works fine. Segger v8.10b give me this error Linking HMI.elf C:/Program Files/SEGGER/SEGGER Embedded Studio 8.10b/lib/libc_v7em_fpv4_sp_d16_hard_t_le_eabi_balanced.a(prinops.o): in function `vfprintf_l': prinops.c:(.text.libc.vfprintf_l+0x5c): undefined reference to `__SEGGER_RTL_vfprintf' Build failed Build failed I returned back to version 7 Thanks Kind Regards Alessandro