diff --git a/7-SGX_Hands-on/src/app/embedded_device.c b/7-SGX_Hands-on/src/app/embedded_device.c
index 390e0e2..1d6b4e0 100644
--- a/7-SGX_Hands-on/src/app/embedded_device.c
+++ b/7-SGX_Hands-on/src/app/embedded_device.c
@@ -21,9 +21,9 @@ typedef struct {
     uint8_t *public_key_path;
 } embedded_device_args;
 
-static EVP_PKEY *read_public_key(uint8_t *public_key_file, EVP_PKEY **key) {
+static EVP_PKEY *read_public_key(uint8_t *public_key_file_path, EVP_PKEY **key) {
     if(public_key_file == NULL) {
-        fprintf(stderr, "public_key_file is a null pointer!\n");
+        fprintf(stderr, "public_key_file_path is a null pointer!\n");
         return NULL;
     }
 
@@ -100,14 +100,13 @@ int main(int argc, char **argv) {
     uint8_t signature[BUFSIZE] = {0};
     size_t signature_size = read(0, signature, BUFSIZE);
     if(signature_size < 70) {
-        printf("failed to read firmware signature\n");
+        fprintf(stderr, "failed to read firmware signature\n");
         goto clean;
     }
 
     hash_firmware(args.firmware_path, &ctx);
     if (EVP_DigestVerifyFinal(ctx, signature, signature_size) != 1) {
-        printf("failed to verify firmware signature\n");
-        goto clean;
+        fprintf(stderr, "failed to verify firmware signature\n");
     }    
 
     clean: ;