diff --git a/main.c b/main.c
index 7a91a88c..a1ff16db 100644
--- a/main.c
+++ b/main.c
@@ -22,8 +22,9 @@
 #include "main.h"
 
 int main(int argc, char * argv[]) {
-	
-  testStr = "cat /proc/cpuinfo | grep 'Revision' | awk '{print $3}' | sed 's/^1000//' | grep '902120'";
+
+  char resbuffer[1000];
+  constant char testStr[] = "cat /proc/cpuinfo | grep 'Revision' | awk '{print $3}' | sed 's/^1000//' | grep '902120'";
   FILE *file_test = sopen(testStr);  // see if Pi Zero 2  
   fgets(resbuffer, 1000, file_test);
   fprintf(stderr, "test result: %s\n", resbuffer);