diff --git a/library/x509_crt.c b/library/x509_crt.c
index 2cbced2..8d07694 100644
--- a/library/x509_crt.c
+++ b/library/x509_crt.c
@@ -2754,8 +2754,8 @@
             p++;
         }
         if (num_digits != 0) {
-            addr[nonzero_groups++] = MBEDTLS_IS_BIG_ENDIAN ? group :
-                                     (group << 8) | (group >> 8);
+            MBEDTLS_PUT_UINT16_BE(group, addr, nonzero_groups);
+            nonzero_groups++;
             if (*p == '\0') {
                 break;
             } else if (*p == '.') {