diff --git a/jdk/make/tools/CharsetMapping/Big5.c2b b/jdk/make/tools/CharsetMapping/Big5.c2b
deleted file mode 100644
index a4ed3176312..00000000000
--- a/jdk/make/tools/CharsetMapping/Big5.c2b
+++ /dev/null
@@ -1,8 +0,0 @@
-#Add the following 5 characters which are duplicated
-#or have conflicts with other characters.
-0xA1C4	0xFF3F	#REGWARN Fallback 0xA1C4 SPACING UNDERSCORE
-0xA2AC	0x2571	#REGWARN Fallback 0xA2AC LT DIAG UP RIGHT TO LOW LEFT
-0xA2AD	0x2572	#REGWARN Fallback 0xA2AD LT DIAG UP LEFT TO LOW RIGHT
-0xA451	0x5341	#REGWARN Fallback 0xA451 HANGZHOU NUMERAL TEN
-0xA4CA	0x5345	#REGWARN Fallback 0xA4CA HANGZHOU NUMERAL THIRTY
-#
diff --git a/jdk/make/tools/CharsetMapping/Big5.map b/jdk/make/tools/CharsetMapping/Big5.map
index dcfa244c310..93242f1ebaa 100644
--- a/jdk/make/tools/CharsetMapping/Big5.map
+++ b/jdk/make/tools/CharsetMapping/Big5.map
@@ -13830,8 +13830,21 @@
 0xF9D4	0x9F49	# <CJK>
 0xF9D5	0x9F98	# <CJK>
 #
+# from Big5.b2c-irreversible
+#
 0xA15A	0xFF3F #SPACING UNDERSCORE
 0xA1FE	0x2571 #LT DIAG UP RIGHT TO LOW LEFT
 0xA240	0x2572 #LT DIAG UP LEFT TO LOW RIGHTG
 0xA2CC	0x5341 #HANGHZOU NUMERAL TEN
 0xA2CE	0x5345 #HANGZHOU NUMERAL THIRTY
+#
+# Add the following 5 characters from Big5.c2b-irreversible
+# It appears these 5 should be here to be the round-trip
+# for these 5 characters. Above 5 are the b->c only nrt.
+#
+0xA1C4	0xFF3F
+0xA2AC	0x2571
+0xA2AD	0x2572
+0xA451	0x5341
+0xA4CA	0x5345
+#