diff --git a/lib/core-net/private-lib-core-net.h b/lib/core-net/private-lib-core-net.h
index 79e85a250..bd3656855 100644
--- a/lib/core-net/private-lib-core-net.h
+++ b/lib/core-net/private-lib-core-net.h
@@ -746,6 +746,7 @@ struct lws {
 	unsigned int client_pipeline:1;
 	unsigned int client_h2_alpn:1;
 	unsigned int client_h2_substream:1;
+	unsigned int client_h2_migrated:1;
 #endif
 
 #ifdef _WIN32
diff --git a/lib/roles/h2/hpack.c b/lib/roles/h2/hpack.c
index 199818776..f5493f7f2 100644
--- a/lib/roles/h2/hpack.c
+++ b/lib/roles/h2/hpack.c
@@ -396,7 +396,7 @@ lws_token_from_index(struct lws *wsi, int index, const char **arg, int *len,
 
 	if (index >= (int)LWS_ARRAY_SIZE(static_token) + dyn->used_entries) {
 		lwsl_info("  %s: adjusted index %d >= %d\n", __func__, index,
-			    dyn->used_entries);
+				(int)LWS_ARRAY_SIZE(static_token) + dyn->used_entries);
 		lws_h2_goaway(wsi, H2_ERR_COMPRESSION_ERROR,
 			      "index out of range");
 		return -1;
@@ -1002,6 +1002,13 @@ int lws_hpack_interpret(struct lws *wsi, unsigned char c)
 			h2n->hpack = HPKS_HLEN_EXT;
 			break;
 		}
+
+		if (h2n->value && !h2n->hpack_len) {
+			lwsl_debug("%s: zero-length header data\n", __func__);
+			h2n->hpack = HPKS_TYPE;
+			goto fin;
+		}
+
 pre_data:
 		h2n->hpack = HPKS_DATA;
 		if (!h2n->value || !h2n->hdr_idx) {
@@ -1179,7 +1186,7 @@ swallow:
 				      "Huffman padding excessive or wrong");
 			return 1;
 		}
-
+fin:
 		if (!h2n->value && (
 		    h2n->hpack_type == HPKT_LITERAL_HDR_VALUE ||
 		    h2n->hpack_type == HPKT_LITERAL_HDR_VALUE_INCR ||
diff --git a/lib/roles/h2/http2.c b/lib/roles/h2/http2.c
index 002dbaf90..363e5586b 100644
--- a/lib/roles/h2/http2.c
+++ b/lib/roles/h2/http2.c
@@ -166,7 +166,8 @@ lws_wsi_server_new(struct lws_vhost *vh, struct lws *parent_wsi,
    	 * connection error (Section 5.4.1) of type PROTOCOL_ERROR.
 	 */
 	if (sid <= h2n->highest_sid_opened) {
-		lwsl_info("%s: tried to open lower sid %d\n", __func__, sid);
+		lwsl_info("%s: tried to open lower sid %d (%d)\n", __func__,
+				sid, h2n->highest_sid_opened);
 		lws_h2_goaway(nwsi, H2_ERR_PROTOCOL_ERROR, "Bad sid");
 		return NULL;
 	}
@@ -1306,7 +1307,7 @@ lws_h2_parse_end_of_frame(struct lws *wsi)
 	case LWS_H2_FRAME_TYPE_SETTINGS:
 
 #if defined(LWS_WITH_CLIENT)
-		if (wsi->client_h2_alpn &&
+		if (wsi->client_h2_alpn && !wsi->client_h2_migrated &&
 		    !(h2n->flags & LWS_H2_FLAG_SETTINGS_ACK)) {
 			struct lws_h2_protocol_send *pps;
 
@@ -1314,7 +1315,8 @@ lws_h2_parse_end_of_frame(struct lws *wsi)
 #if defined(LWS_WITH_FILE_OPS)
 			wsi->http.fop_fd = NULL;
 #endif
-
+			lwsl_info("%s: migrating\n", __func__);
+			wsi->client_h2_migrated = 1;
 			/*
 			 * we need to treat the headers from the upgrade as the
 			 * first job.  So these need to get shifted to sid 1.
diff --git a/lib/roles/http/parsers.c b/lib/roles/http/parsers.c
index 1897aa867..51ff6b9bb 100644
--- a/lib/roles/http/parsers.c
+++ b/lib/roles/http/parsers.c
@@ -1078,13 +1078,14 @@ swallow:
 				c += 'a' - 'A';
 
 #if defined(LWS_WITH_CUSTOM_HEADERS)
+
 			/*
 			 * ...in case it's an unknown header, speculatively
 			 * store it as the name comes in.  If we recognize it as
 			 * a known header, we'll snip this.
 			 */
 
-			if (!ah->unk_pos) {
+			if (!wsi->http2_substream && !ah->unk_pos) {
 				ah->unk_pos = ah->pos;
 				/*
 				 * Prepare new unknown header linked-list entry
@@ -1106,7 +1107,7 @@ swallow:
 			pos = ah->lextable_pos;
 
 #if defined(LWS_WITH_CUSTOM_HEADERS)
-			if (pos < 0 && c == ':') {
+			if (!wsi->http2_substream && pos < 0 && c == ':') {
 				/*
 				 * process unknown headers
 				 *
@@ -1170,13 +1171,16 @@ nope:
 				/* b7 = 0, end or 3-byte */
 				if (lextable[pos] < FAIL_CHAR) {
 #if defined(LWS_WITH_CUSTOM_HEADERS)
-					/*
-					 * We hit a terminal marker, so we
-					 * recognized this header... drop the
-					 * speculative name part storage
-					 */
-					ah->pos = ah->unk_pos;
-					ah->unk_pos = 0;
+					if (!wsi->http2_substream) {
+						/*
+						 * We hit a terminal marker, so
+						 * we recognized this header...
+						 * drop the speculative name
+						 * part storage
+						 */
+						ah->pos = ah->unk_pos;
+						ah->unk_pos = 0;
+					}
 #endif
 					ah->lextable_pos = pos;
 					break;
@@ -1213,19 +1217,25 @@ nope:
 #if !defined(LWS_WITH_CUSTOM_HEADERS)
 						ah->parser_state = WSI_TOKEN_SKIPPING;
 #endif
+						if (wsi->http2_substream)
+							ah->parser_state = WSI_TOKEN_SKIPPING;
 						break;
 					}
 
-				if (m != LWS_ARRAY_SIZE(methods))
+				if (m != LWS_ARRAY_SIZE(methods)) {
 #if defined(LWS_WITH_CUSTOM_HEADERS)
 					/*
 					 * We have the method, this is just an
 					 * unknown header then
 					 */
-					goto unknown_hdr;
+					if (!wsi->http2_substream)
+						goto unknown_hdr;
+					else
+						break;
 #else
 					break;
 #endif
+				}
 				/*
 				 * ...it's an unknown http method from a client
 				 * in fact, it cannot be valid http.
@@ -1246,15 +1256,15 @@ nope:
 			}
 			if (ah->lextable_pos < 0) {
 #if defined(LWS_WITH_CUSTOM_HEADERS)
-				goto unknown_hdr;
-#else
+				if (!wsi->http2_substream)
+					goto unknown_hdr;
+#endif
 				/*
 				 * ...otherwise for a client, let him ignore
 				 * unknown headers coming from the server
 				 */
 				ah->parser_state = WSI_TOKEN_SKIPPING;
 				break;
-#endif
 			}
 
 			if (lextable[ah->lextable_pos] < FAIL_CHAR) {
@@ -1301,7 +1311,8 @@ nope:
 unknown_hdr:
 			//ah->parser_state = WSI_TOKEN_SKIPPING;
 			//break;
-			break;
+			if (!wsi->http2_substream)
+				break;
 #endif
 
 start_fragment: