diff --git a/src/mux_fcgi.c b/src/mux_fcgi.c
index 4c2310be4..4adf658b5 100644
--- a/src/mux_fcgi.c
+++ b/src/mux_fcgi.c
@@ -3994,8 +3994,7 @@ static size_t fcgi_snd_buf(struct stconn *sc, struct buffer *buf, size_t count,
 
 	while (fstrm->state < FCGI_SS_HLOC && !(fstrm->flags & FCGI_SF_BLK_ANY) &&
 	       count && !htx_is_empty(htx)) {
-		blk = htx_get_head_blk(htx);
-		ALREADY_CHECKED(blk);
+		blk = ASSUME_NONNULL(htx_get_head_blk(htx));
 		bsize = htx_get_blksz(blk);
 
 		switch (htx_get_blk_type(blk)) {