diff --git a/include/types/h1.h b/include/types/h1.h
index ec8cca0..2dd58dd 100644
--- a/include/types/h1.h
+++ b/include/types/h1.h
@@ -139,6 +139,7 @@
 #define H1_MF_CLEN              0x00000001 // content-length present
 #define H1_MF_CHNK              0x00000002 // chunk present, exclusive with c-l
 #define H1_MF_RESP              0x00000004 // this message is the response message
+#define H1_MF_TOLOWER           0x00000008 // turn the header names to lower case
 
 
 /* basic HTTP/1 message state for use in parsers. The err_pos field is special,
diff --git a/src/h1.c b/src/h1.c
index db71789..47af9be 100644
--- a/src/h1.c
+++ b/src/h1.c
@@ -1082,7 +1082,7 @@
 		/* assumes sol points to the first char */
 		if (likely(HTTP_IS_TOKEN(*ptr))) {
 			/* turn it to lower case if needed */
-			if (isupper((unsigned char)*ptr))
+			if (isupper((unsigned char)*ptr) && h1m->flags & H1_MF_TOLOWER)
 				*ptr = tolower(*ptr);
 			EAT_AND_JUMP_OR_RETURN(ptr, end, http_msg_hdr_name, http_msg_ood, state, H1_MSG_HDR_NAME);
 		}
@@ -1231,11 +1231,11 @@
 				h1m->flags |= H1_MF_CLEN;
 				h1m->curr_len = h1m->body_len = 0;
 			}
-			else if (isteq(n, ist("transfer-encoding"))) {
+			else if (isteqi(n, ist("transfer-encoding"))) {
 				h1m->flags &= ~H1_MF_CLEN;
 				h1m->flags |= H1_MF_CHNK;
 			}
-			else if (isteq(n, ist("content-length")) && !(h1m->flags & H1_MF_CHNK)) {
+			else if (isteqi(n, ist("content-length")) && !(h1m->flags & H1_MF_CHNK)) {
 				h1m->flags |= H1_MF_CLEN;
 				strl2llrc(v.ptr, v.len, &cl);
 				h1m->curr_len = h1m->body_len = cl;
diff --git a/src/mux_h2.c b/src/mux_h2.c
index 9205c2f..780bc57 100644
--- a/src/mux_h2.c
+++ b/src/mux_h2.c
@@ -694,6 +694,7 @@
 	h2s->rxbuf     = BUF_NULL;
 	h1m_init_res(&h2s->h1m);
 	h2s->h1m.err_pos = -1; // don't care about errors on the response path
+	h2s->h1m.flags |= H1_MF_TOLOWER;
 	h2s->by_id.key = h2s->id = id;
 	h2c->max_id    = id;
 
@@ -3239,6 +3240,7 @@
 		/* we'll let the caller check if it has more headers to send */
 		h1m_init_res(h1m);
 		h1m->err_pos = -1; // don't care about errors on the response path
+		h2s->h1m.flags |= H1_MF_TOLOWER;
 		goto end;
 	}