diff --git a/proj/intercept/src/intercept.c b/proj/intercept/src/intercept.c
index 9e01b87..d666055 100644
--- a/proj/intercept/src/intercept.c
+++ b/proj/intercept/src/intercept.c
@@ -546,10 +546,10 @@ static uint8_t func_flags[256];
 static size_t msg_bytes(char *buf, size_t maxlen, size_t len, const char *str, int flags) {
     size_t offset = flags & 1 ? snprintf(buf, maxlen, "\"") : snprintf(buf, maxlen, "%p:\"", str);
     for (int i = 0; i < len && offset <= maxlen - 2; i++) {
-        char ch = str[i];
+        const uint8_t ch = str[i];
         if (ch == '\\' || ch == '"') {
             buf[offset++] = '\\';
-            buf[offset++] = ch;
+            buf[offset++] = (char)ch;
         } else if (ch == '\t') {
             buf[offset++] = '\\';
             buf[offset++] = 't';
@@ -559,10 +559,10 @@ static size_t msg_bytes(char *buf, size_t maxlen, size_t len, const char *str, i
         } else if (ch == '\r') {
             buf[offset++] = '\\';
             buf[offset++] = 'r';
-        } else if ((ch >= 0 && ch < 0x20) || ch == 0x7F) {
+        } else if (ch < 0x20 || ch >= 0x7F) {
             offset += snprintf(buf + offset, maxlen - offset, "\\x%02x", ch);
         } else {
-            buf[offset++] = ch;
+            buf[offset++] = (char)ch;
         }
     }
     if (offset <= maxlen - 2) {