diff --git a/src/pn532/pn532.cxx b/src/pn532/pn532.cxx
index d0e7b221..2ac512d2 100644
--- a/src/pn532/pn532.cxx
+++ b/src/pn532/pn532.cxx
@@ -995,7 +995,8 @@ bool PN532::mifareclassic_WriteNDEFURI (uint8_t sectorNumber,
   // Setup the sector buffer (w/pre-formatted TLV wrapper and NDEF message)
   uint8_t sectorbuffer1[16] = {0x00, 0x00, 0x03, static_cast<uint8_t>(len+5),
                                0xD1, 0x01, static_cast<uint8_t>(len+1),
-                               0x55, uriIdentifier, 0x00, 0x00, 0x00, 0x00, 
+                               0x55, static_cast<uint8_t>(uriIdentifier), 
+                               0x00, 0x00, 0x00, 0x00, 
                                0x00, 0x00, 0x00};
   uint8_t sectorbuffer2[16] = {0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
                                0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
@@ -1337,7 +1338,7 @@ bool PN532::ntag2xx_WriteNDEFURI (NDEF_URI_T uriIdentifier, char * url,
       0x01,         /* Type Length for the record type indicator */
       static_cast<uint8_t>(len+1),        /* Payload len */
       0x55,         /* Record Type Indicator (0x55 or 'U' = URI Record) */
-      uriIdentifier /* URI Prefix (ex. 0x01 = "http://www.") */
+      static_cast<uint8_t>(uriIdentifier) /* URI Prefix (ex. 0x01 = "http://www.") */
     };
   
   // Write 12 byte header (three pages of data starting at page 4)