diff --git a/upnp/src/genlib/net/http/webserver.c b/upnp/src/genlib/net/http/webserver.c
index dbecfb0..0bd0f84 100644
--- a/upnp/src/genlib/net/http/webserver.c
+++ b/upnp/src/genlib/net/http/webserver.c
@@ -867,8 +867,8 @@ static int CreateHTTPRangeResponseHeader(
 					sizeof(Instr->RangeHeader),
 					"CONTENT-RANGE: bytes %" PRId64
 					"-%" PRId64 "/%" PRId64 "\r\n",
-					(int64_t)(FileLength - LastByte + 1),
-					(int64_t)FileLength,
+					(int64_t)(FileLength - LastByte),
+					(int64_t)FileLength - 1,
 					(int64_t)FileLength);
 			}
 			if (rc < 0 || (unsigned int) rc >= sizeof(Instr->RangeHeader)) {