diff --git a/src/include/ipxe/icmpv6.h b/src/include/ipxe/icmpv6.h
index db5bec2d..0474ddca 100644
--- a/src/include/ipxe/icmpv6.h
+++ b/src/include/ipxe/icmpv6.h
@@ -40,6 +40,18 @@ struct icmpv6_handler {
 /** Declare an ICMPv6 handler */
 #define __icmpv6_handler __table_entry ( ICMPV6_HANDLERS, 01 )
 
+/** ICMPv6 destination unreachable */
+#define ICMPV6_DESTINATION_UNREACHABLE 1
+
+/** ICMPv6 packet too big */
+#define ICMPV6_PACKET_TOO_BIG 2
+
+/** ICMPv6 time exceeded */
+#define ICMPV6_TIME_EXCEEDED 3
+
+/** ICMPv6 parameter problem */
+#define ICMPV6_PARAMETER_PROBLEM 4
+
 /** ICMPv6 echo request */
 #define ICMPV6_ECHO_REQUEST 128
 
diff --git a/src/net/icmpv6.c b/src/net/icmpv6.c
index 45a34440..8555aaf0 100644
--- a/src/net/icmpv6.c
+++ b/src/net/icmpv6.c
@@ -38,6 +38,65 @@ FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
  *
  */
 
+/* Disambiguate the various error causes */
+#define EHOSTUNREACH_ROUTE						\
+	__einfo_error ( EINFO_EHOSTUNREACH_ROUTE )
+#define EINFO_EHOSTUNREACH_ROUTE					\
+	__einfo_uniqify ( EINFO_EHOSTUNREACH, 0,			\
+			  "No route to destination" )
+#define EHOSTUNREACH_PROHIBITED						\
+	__einfo_error ( EINFO_EHOSTUNREACH_PROHIBITED )
+#define EINFO_EHOSTUNREACH_PROHIBITED					\
+	__einfo_uniqify ( EINFO_EHOSTUNREACH, 1,			\
+			  "Communication administratively prohibited" )
+#define EHOSTUNREACH_ADDRESS						\
+	__einfo_error ( EINFO_EHOSTUNREACH_ADDRESS )
+#define EINFO_EHOSTUNREACH_ADDRESS					\
+	__einfo_uniqify ( EINFO_EHOSTUNREACH, 3,			\
+			  "Address unreachable" )
+#define EHOSTUNREACH_PORT						\
+	__einfo_error ( EINFO_EHOSTUNREACH_PORT )
+#define EINFO_EHOSTUNREACH_PORT						\
+	__einfo_uniqify ( EINFO_EHOSTUNREACH, 4,			\
+			  "Port unreachable" )
+#define EHOSTUNREACH_CODE( code )					\
+	EUNIQ ( EINFO_EHOSTUNREACH, ( (code) & 0x1f ),			\
+		EHOSTUNREACH_ROUTE, EHOSTUNREACH_PROHIBITED,		\
+		EHOSTUNREACH_ADDRESS, EHOSTUNREACH_PORT )
+
+#define ETIMEDOUT_HOP							\
+	__einfo_error ( EINFO_ETIMEDOUT_HOP )
+#define EINFO_ETIMEDOUT_HOP						\
+	__einfo_uniqify ( EINFO_ETIMEDOUT, 0,				\
+			  "Hop limit exceeded in transit" )
+#define ETIMEDOUT_REASSEMBLY						\
+	__einfo_error ( EINFO_ETIMEDOUT_REASSEMBLY )
+#define EINFO_ETIMEDOUT_REASSEMBLY					\
+	__einfo_uniqify ( EINFO_ETIMEDOUT, 1,				\
+			  "Fragment reassembly time exceeded" )
+#define ETIMEDOUT_CODE( code )						\
+	EUNIQ ( EINFO_ETIMEDOUT, ( (code) & 0x1f ),			\
+		ETIMEDOUT_HOP, ETIMEDOUT_REASSEMBLY )
+
+#define EPROTO_BAD_HEADER						\
+	__einfo_error ( EINFO_EPROTO_BAD_HEADER )
+#define EINFO_EPROTO_BAD_HEADER						\
+	__einfo_uniqify ( EINFO_EPROTO, 0,				\
+			  "Erroneous header field" )
+#define EPROTO_NEXT_HEADER						\
+	__einfo_error ( EINFO_EPROTO_NEXT_HEADER )
+#define EINFO_EPROTO_NEXT_HEADER					\
+	__einfo_uniqify ( EINFO_EPROTO, 1,				\
+			  "Unrecognised next header type" )
+#define EPROTO_OPTION							\
+	__einfo_error ( EINFO_EPROTO_OPTION )
+#define EINFO_EPROTO_OPTION						\
+	__einfo_uniqify ( EINFO_EPROTO, 2,				\
+			  "Unrecognised IPv6 option" )
+#define EPROTO_CODE( code )						\
+	EUNIQ ( EINFO_EPROTO, ( (code) & 0x1f ),			\
+		EPROTO_BAD_HEADER, EPROTO_NEXT_HEADER, EPROTO_OPTION )
+
 struct icmp_echo_protocol icmpv6_echo_protocol __icmp_echo_protocol;
 
 /**
@@ -148,8 +207,25 @@ static int icmpv6_rx ( struct io_buffer *iobuf, struct net_device *netdev,
 	/* Identify handler */
 	handler = icmpv6_handler ( icmp->type );
 	if ( ! handler ) {
-		DBGC ( netdev, "ICMPv6 unrecognised type %d\n", icmp->type );
-		rc = -ENOTSUP;
+		switch ( icmp->type ) {
+		case ICMPV6_DESTINATION_UNREACHABLE:
+			rc = -EHOSTUNREACH_CODE ( icmp->code );
+			break;
+		case ICMPV6_PACKET_TOO_BIG:
+			rc = -ERANGE;
+			break;
+		case ICMPV6_TIME_EXCEEDED:
+			rc = -ETIMEDOUT_CODE ( icmp->code );
+			break;
+		case ICMPV6_PARAMETER_PROBLEM:
+			rc = -EPROTO_CODE ( icmp->code );
+			break;
+		default:
+			DBGC ( netdev, "ICMPv6 unrecognised type %d code %d\n",
+			       icmp->type, icmp->code );
+			rc = -ENOTSUP;
+			break;
+		};
 		goto done;
 	}