(a) A debtor or secondary obligor may waive the right to notification of disposition of collateral under § 4-9-611 only by an agreement to that effect entered into and signed after default.
(b) A debtor may waive the right to require disposition of collateral under § 4-9-620(e) only by an agreement to that effect entered into and signed after default.
(c) Except in a consumer-goods transaction, a debtor or secondary obligor may waive the right to redeem collateral under § 4-9-623 only by an agreement to that effect entered into and signed after default.