diff --git a/module/zfs/zap_micro.c b/module/zfs/zap_micro.c
index 920b529ca6..8b4fd0652a 100644
--- a/module/zfs/zap_micro.c
+++ b/module/zfs/zap_micro.c
@@ -1283,19 +1283,8 @@ zap_update(objset_t *os, uint64_t zapobj, const char *name,
     int integer_size, uint64_t num_integers, const void *val, dmu_tx_t *tx)
 {
 	zap_t *zap;
-	ASSERTV(uint64_t oldval);
 	const uint64_t *intval = val;
 
-#ifdef ZFS_DEBUG
-
-	/*
-	 * If there is an old value, it shouldn't change across the
-	 * lockdir (eg, due to bprewrite's xlation).
-	 */
-	if (integer_size == 8 && num_integers == 1)
-		(void) zap_lookup(os, zapobj, name, 8, 1, &oldval);
-#endif
-
 	int err =
 	    zap_lockdir(os, zapobj, tx, RW_WRITER, TRUE, TRUE, FTAG, &zap);
 	if (err != 0)
@@ -1322,7 +1311,6 @@ zap_update(objset_t *os, uint64_t zapobj, const char *name,
 	} else {
 		mzap_ent_t *mze = mze_find(zn);
 		if (mze != NULL) {
-			ASSERT3U(MZE_PHYS(zap, mze)->mze_value, ==, oldval);
 			MZE_PHYS(zap, mze)->mze_value = *intval;
 		} else {
 			mzap_addent(zn, *intval);