diff --git a/kpack_c.c b/kpack_c.c
index 86f6c56..d9e4ccd 100644
--- a/kpack_c.c
+++ b/kpack_c.c
@@ -16,6 +16,9 @@
 #define METHOD_FLAG_CALLTRICK_1 0x40
 #define METHOD_FLAG_CALLTRICK_2 0x80
 
+#define OP_CALL_REL32 0xE8
+#define OP_JMP_REL32  0xE9
+
 static const char* str_usage = "Usage: %s [--nologo / -n] [--kernel / -k] [--unpack / -u] <infile> [<outfile>]\n";
 
 static void error_load_infile() {
@@ -60,10 +63,7 @@ unsigned preprocess_calltrick(unsigned char *infile, unsigned insize, unsigned c
     do {
         //printf("infile_ptr = %p, count = %u\n", infile_ptr, count);
         unsigned opcode = *(infile_ptr++);
-        // E8 dword: call rel32
-        // E9 dword: jmp rel32
-        if (opcode > 0xE9)
-        {
+        if (opcode != OP_CALL_REL32 && opcode != OP_JMP_REL32) {
             continue;
         }
         if (count < 5) {