diff --git a/crypto/ec/ecp_nistp224.c b/crypto/ec/ecp_nistp224.c
index 9a59ef0c1..ed09f97ad 100644
--- a/crypto/ec/ecp_nistp224.c
+++ b/crypto/ec/ecp_nistp224.c
@@ -321,7 +321,7 @@ static void bin28_to_felem(felem out, const u8 in[28])
     out[0] = *((const uint64_t *)(in)) & 0x00ffffffffffffff;
     out[1] = (*((const uint64_t *)(in + 7))) & 0x00ffffffffffffff;
     out[2] = (*((const uint64_t *)(in + 14))) & 0x00ffffffffffffff;
-    out[3] = (*((const uint64_t *)(in + 21))) & 0x00ffffffffffffff;
+    out[3] = (*((const uint64_t *)(in+20))) >> 8;
 }
 
 static void felem_to_bin28(u8 out[28], const felem in)