diff --git a/ch3-coop/os/Makefile b/ch3-coop/os/Makefile
index 0c03143..2b314fb 100644
--- a/ch3-coop/os/Makefile
+++ b/ch3-coop/os/Makefile
@@ -4,7 +4,7 @@ MODE := release
 KERNEL_ELF := target/$(TARGET)/$(MODE)/os
 KERNEL_BIN := $(KERNEL_ELF).bin
 SYMBOL_MAP := target/system.map
-QEMU_CMD_PATH := ../../tools/qemu-system-riscv64
+QEMU_CMD_PATH := /Users/zhangxinyu/Downloads/qemu-7.0.0/build/qemu-system-riscv64
 QEMU_PID = $(shell ps aux | grep "[q]emu-system' | awk '{print $$2}")
 OBJDUMP := rust-objdump --arch-name=riscv64
 OBJCOPY := rust-objcopy --binary-architecture=riscv64
diff --git a/tools/qemu-system-riscv64 b/tools/qemu-system-riscv64
deleted file mode 100755
index fb8f252..0000000
Binary files a/tools/qemu-system-riscv64 and /dev/null differ
diff --git a/tools/riscv64-unknown-elf-gdb b/tools/riscv64-unknown-elf-gdb
deleted file mode 100755
index dcf0f97..0000000
Binary files a/tools/riscv64-unknown-elf-gdb and /dev/null differ