--- Makefile	2022-03-24 18:31:27.962398473 +0900
+++ Makefile.picolibc	2022-03-24 19:54:20.005720825 +0900
@@ -216,7 +216,7 @@ LDFLAGS_F7 =-T stm32f7xx_link.ld $(MCFLA
 # Common flags
 CFLAGS=-Os -ffunction-sections -fdata-sections -nostdlib -DCUSTOM_NEW -DNO_EXCEPTIONS -Wno-unused-parameter -nostdlib
 CXXFLAGS=-Os -fno-exceptions -ffunction-sections -fdata-sections -nostdlib -fno-rtti -DCUSTOM_NEW -DNO_EXCEPTIONS -Wno-unused-parameter
-LDFLAGS=-Os --specs=nano.specs --specs=nosys.specs
+LDFLAGS=-Os --specs=picolibc.specs --oslib=semihost
 
 # Build Rules
 .PHONY: all release_f1 release_f4 release_f7 hs bl nobl pi-f4 f446 f767 clean