diff --git a/software/obsolete/osmo_e1f.c b/software/obsolete/osmo_e1f.c
index cbcd0db..a4cadb2 100644
--- a/software/obsolete/osmo_e1f.c
+++ b/software/obsolete/osmo_e1f.c
@@ -208,6 +208,12 @@
 {
 	uint8_t ret = 0;
 
+	/* re-set CRC4 at start of sub-multiframe */
+	if (e1i->tx.frame_nr == 0 || e1i->tx.frame_nr == 8) {
+		e1i->tx.crc4_last_smf = e1i->tx.crc4;
+		e1i->tx.crc4 = 0;
+	}
+
 	/* according to Table 5B/G.704 - CRC-4 multiframe structure */
 	if ((e1i->tx.frame_nr % 2) == 0) {
 		/* FAS */
@@ -236,12 +242,6 @@
 			ret |= 0x20;
 	}
 
-	/* re-set CRC4 at start of sub-multiframe */
-	if (e1i->tx.frame_nr == 0 || e1i->tx.frame_nr == 8) {
-		e1i->tx.crc4_last_smf = e1i->tx.crc4;
-		e1i->tx.crc4 = 0;
-	}
-
 	/* increment frame number modulo 16 */
 	e1i->tx.frame_nr = (e1i->tx.frame_nr + 1) % 16;