From b52308d0712a89b51602844eae37fbc6979968af Mon Sep 17 00:00:00 2001
From: Philippe Teuwen <yobibe@gmail.com>
Date: Thu, 29 Aug 2013 22:23:01 +0200
Subject: [PATCH] TypeB ProtocolInfo: limit mask for ISO14443-4 support flag

---
 libnfc/target-subr.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/libnfc/target-subr.c b/libnfc/target-subr.c
index b846b6e..b99b28c 100644
--- a/libnfc/target-subr.c
+++ b/libnfc/target-subr.c
@@ -544,7 +544,9 @@ snprint_nfc_iso14443b_info(char *dst, size_t size, const nfc_iso14443b_info *pnb
       const int iMaxFrameSizes[] = { 16, 24, 32, 40, 48, 64, 96, 128, 256 };
       off += snprintf(dst + off, size - off, "* Maximum frame sizes: %d bytes\n", iMaxFrameSizes[((pnbi->abtProtocolInfo[1] & 0xf0) >> 4)]);
     }
-    if ((pnbi->abtProtocolInfo[1] & 0x0f) == PI_ISO14443_4_SUPPORTED) {
+    if ((pnbi->abtProtocolInfo[1] & 0x01) == PI_ISO14443_4_SUPPORTED) {
+      // in principle low nibble could only be 0000 or 0001 and other values are RFU
+      // but in practice we found 0011 so let's use only last bit for -4 compatibility
       off += snprintf(dst + off, size - off, "* Protocol types supported: ISO/IEC 14443-4\n");
     }
     off += snprintf(dst + off, size - off, "* Frame Waiting Time: %.4g ms\n", 256.0 * 16.0 * (1 << ((pnbi->abtProtocolInfo[2] & 0xf0) >> 4)) / 13560.0);