diff --git a/src/openvpn/crypto.c b/src/openvpn/crypto.c
index 3d79fe5..ee43d65 100644
--- a/src/openvpn/crypto.c
+++ b/src/openvpn/crypto.c
@@ -1473,9 +1473,9 @@
                     hex_byte[hb_index++] = c;
                     if (hb_index == 2)
                     {
-                        uint8_t u;
-                        ASSERT(sscanf((const char *)hex_byte, "%" SCNx8, &u) == 1);
-                        *out++ = u;
+                        unsigned int u;
+                        ASSERT(sscanf((const char *)hex_byte, "%2x", &u) == 1);
+                        *out++ = (uint8_t)u;
                         hb_index = 0;
                         if (++count == keylen)
                         {
diff --git a/src/openvpn/cryptoapi.c b/src/openvpn/cryptoapi.c
index bf80bbd..0f95ab7 100644
--- a/src/openvpn/cryptoapi.c
+++ b/src/openvpn/cryptoapi.c
@@ -169,10 +169,12 @@
             break;
         }
 
-        if (!isxdigit(p[0]) || !isxdigit(p[1]) || sscanf(p, "%2hhx", &arr[i++]) != 1)
+        unsigned int b;
+        if (!isxdigit(p[0]) || !isxdigit(p[1]) || sscanf(p, "%2x", &b) != 1)
         {
             return 0;
         }
+        arr[i++] = (unsigned char)b;
     }
     return i;
 }