diff --git a/gfx/2d/ScaledFontMac.cpp b/gfx/2d/ScaledFontMac.cpp
index 1d8378aae..74e157b69 100644
--- a/gfx/2d/ScaledFontMac.cpp
+++ b/gfx/2d/ScaledFontMac.cpp
@@ -219,9 +219,11 @@ struct writeBuf
 };
 
 #ifdef __ppc__
-#define TAG_CFF 0x43464620
+#define TAG_CFF  0x43464620
+#define TAG_HEAD 0x68656164
 #else
-#define TAG_CFF 0x20464643
+#define TAG_CFF  0x20464643
+#define TAG_HEAD 0x64616568
 #endif
 
 bool
@@ -246,7 +248,7 @@ ScaledFontMac::GetFontFileData(FontFileDataOutput aDataCallback, void *aBaton)
         records[i].offset = offset;
         records[i].data = data;
         records[i].length = CFDataGetLength(data);
-        bool skipChecksumAdjust = (tag == 0x68656164); // 'head'
+        bool skipChecksumAdjust = (tag == TAG_HEAD); // 'head'
         records[i].checkSum = CalcTableChecksum(reinterpret_cast<const uint32_t*>(CFDataGetBytePtr(data)),
                                                 records[i].length, skipChecksumAdjust);
         offset += records[i].length;
@@ -309,7 +311,7 @@ ScaledFontMac::GetFontFileData(FontFileDataOutput aDataCallback, void *aBaton)
 	}
         records[i].data = data;
         records[i].length = (uint32_t)dataLength;
-        bool skipChecksumAdjust = (tag == 0x68656164); // 'head'
+        bool skipChecksumAdjust = (tag == TAG_HEAD); // 'head'
         records[i].checkSum = CalcTableChecksum(
 		reinterpret_cast<const uint32_t*>(CFDataGetBytePtr(data)),
                 records[i].length, skipChecksumAdjust);
@@ -342,7 +344,7 @@ ScaledFontMac::GetFontFileData(FontFileDataOutput aDataCallback, void *aBaton)
     // write tables
     int checkSumAdjustmentOffset = 0;
     for (CFIndex i = 0; i<count; i++) {
-        if (records[i].tag == 0x68656164) {
+        if (records[i].tag == TAG_HEAD) {
             checkSumAdjustmentOffset = buf.offset + 2*4;
         }
         buf.writeMem(CFDataGetBytePtr(records[i].data), CFDataGetLength(records[i].data));