diff --git a/library/oid.c b/library/oid.c
index fcff152..d8ba773 100644
--- a/library/oid.c
+++ b/library/oid.c
@@ -796,14 +796,39 @@
     p = buf;
     n = size;
 
-    /* First byte contains first two dots */
-    if (oid->len > 0) {
-        ret = mbedtls_snprintf(p, n, "%d.%d", oid->p[0] / 40, oid->p[0] % 40);
-        OID_SAFE_SNPRINTF;
+    /* First subidentifier contains first two OID components */
+    i = 0;
+    value = 0;
+    while (i < oid->len && ((oid->p[i] & 0x80) != 0)) {
+        /* Prevent overflow in value. */
+        if (((value << 7) >> 7) != value) {
+            return MBEDTLS_ERR_OID_BUF_TOO_SMALL;
+        }
+
+        value += oid->p[i] & 0x7F;
+        value <<= 7;
+        i++;
     }
+    if (i >= oid->len) {
+        return MBEDTLS_ERR_OID_BUF_TOO_SMALL;
+    }
+    /* Last byte of first subidentifier */
+    value += oid->p[i] & 0x7F;
+    i++;
+
+    unsigned int component1 = value / 40;
+    if (component1 > 2) {
+        /* The first component can only be 0, 1 or 2.
+         * If oid->p[0] / 40 is greater than 2, the leftover belongs to
+         * the second component. */
+        component1 = 2;
+    }
+    unsigned int component2 = value - (40 * component1);
+    ret = mbedtls_snprintf(p, n, "%u.%u", component1, component2);
+    OID_SAFE_SNPRINTF;
 
     value = 0;
-    for (i = 1; i < oid->len; i++) {
+    for (; i < oid->len; i++) {
         /* Prevent overflow in value. */
         if (((value << 7) >> 7) != value) {
             return MBEDTLS_ERR_OID_BUF_TOO_SMALL;