(a) A debtor or secondary obligor may waive the right to notification of disposition of collateral under § 9.611 only by an agreement to that effect entered into and authenticated after default.
(b) A debtor may waive the right to require disposition of collateral under § 9.620(e) only by an agreement to that effect entered into and authenticated after default.

(c) Except in a consumer-goods transaction, a debtor or secondary obligor may waive the right to redeem collateral under § 9.623 only by an agreement to that effect entered into and authenticated after default.