| # apebs = # wlar, wlar[vtblpnum] = wl-entry(m1, used), wlar[vtblpnum0] = wl-entry(m0, free), apebs[vtblpnum] = mkpeb(aehdr, avhdr0, buf0, m2, false), apebs1 = apebs, err = err0, q1 = q, vols1 = vols, wlar0 = wlar, vtblpnum < # wlar, vtblpnum0 < # wlar, bflipset-cons(bflipset0, wlar), ubi-io-inv(apebs), ubi-io-peb-inv(mkpeb(aehdr, avhdr0, buf0, m2, false)), unique-sqns(apebs), valid-ebatbl(apebs, wlar, vols, n0), valid-eraseq(q), valid-eraseq(wlar, q), valid-eraseq(apebs, q), valid-global-sqn(apebs, n1), valid-vtbl(apebs, vols, wlar, n0), valid-wl(apebs, wlar), m1 + WL_THRESHOLD ≤ m0, ⌊err0⌋ ∨ err0 = ESUCCESS ⊦ [skip] ( # apebs = # wlar ∧ unique-sqns(apebs) ∧ valid-global-sqn(apebs, n1) ∧ valid-wl(apebs, wlar) ∧ valid-eraseq(q) ∧ valid-eraseq(wlar, q) ∧ valid-eraseq(apebs, q) ∧ ¬ VTBL_VOLID ∈ vols ∧ bflipset-cons(bflipset0, wlar) ∧ valid-ebatbl(apebs, wlar, vols, n0) ∧ valid-vtbl(apebs, vols, wlar, n0) ∧ ubi-io-inv(apebs) ∧ ( vols1 = vols ∧ id(apebs, apebs1, mapped-pebs(vols)) ∧ q.lebrefs ⊆ q1.lebrefs ++ (VTBL_VOLID × VTBL_LNUM) ∨ (∃ v, m, n. v ∈ vols1 ∧ m < # vols1[v] ∧ vols1[v][m] ≠ unmapped ∧ vols = vols1[v, vols1[v][m, ⌜n⌝ ]] ∧ id(apebs, apebs1, mapped-pebs(vols1) -- vols1[v][m].pnum) ∧ apebs[n].data = apebs1[vols1[v][m].pnum].data ∧ apebs[n].fill ≤ apebs1[vols1[v][m].pnum].fill ∧ q.lebrefs ⊆ q1.lebrefs ++ (v × m))) → err = ESUCCESS → Δ wlar < Δ wlar0), err = ESUCCESS, VTBL_VOLID ∈ vols |