| # apebs0 = # wlar, # apebs = # wlar, # wlar1 = # wlar, Δ wlar0 + m0 = Δ wlar, vols[v][m] = ⌜vtblpnum2⌝ , wlar[vtblpnum2] = wl-entry(m1, used), wlar[vtblpnum1] = wl-entry(m4, free), apebs[vtblpnum2] = mkpeb(aechdr(m1), avidhdr(v0, m3, valid-sqns(v, m, apebs).max, m5, m6), buf, m2, false), apebs0[vtblpnum1] = mkpeb(aehdr, avhdr, buf, align↑(datasize(buf, LEB_SIZE), EB_PAGE_SIZE), boolvar), wlar1[vtblpnum2] = wl-entry(m1, stat), wlar1[vtblpnum1] = wl-entry(m4, stat0), ecs(wlar1) = ecs(wlar), q0 = q + eq-entry(vtblpnum2, v × m) ', Δ wlar1 = Δ wlar, vtblpnum1 < # wlar, m < # vols[v], vtblpnum2 < # wlar, m1 + UBI_ERASE_RETRIES < ecs(wlar).max, bflipset-cons(bflipset, wlar1), bflipset-cons(bflipset0, wlar), id(apebs0, apebs, mapped-pebs(vols)), id○(apebs0, apebs, vtblpnum1), is-aligned(LEB_SIZE, EB_PAGE_SIZE), ubi-io-inv(apebs0), ubi-io-inv(apebs), ubi-io-peb-inv(mkpeb(aechdr(m1), avidhdr(v0, m3, valid-sqns(v, m, apebs).max, m5, m6), buf, m2, false)), ubi-io-peb-inv(mkpeb(aehdr, avhdr, buf, align↑(datasize(buf, LEB_SIZE), EB_PAGE_SIZE), boolvar)), unique-sqns(apebs0), unique-sqns(apebs), valid-ebatbl(apebs0, wlar1, vols[v, vols[v][m, ⌜vtblpnum1⌝ ]], n0), valid-eraseq(q + eq-entry(vtblpnum2, v × m) '), valid-eraseq(wlar1, q + eq-entry(vtblpnum2, v × m) '), valid-eraseq(apebs0, q + eq-entry(vtblpnum2, v × m) '), valid-eraseq(q), valid-eraseq(wlar, q), valid-eraseq(apebs, q), valid-global-sqn(apebs0, n), valid-global-sqn(apebs, n1), valid-peb(v, m, mkpeb(aechdr(m1), avidhdr(v0, m3, valid-sqns(v, m, apebs).max, m5, m6), buf, m2, false)), valid-vtbl(apebs0, vols, wlar1, n0), valid-vtbl(apebs, vols, wlar, n2), valid-wl(apebs0, wlar1), v ∈ vols, m0 ≤ UBI_ERASE_RETRIES + 1, m1 + WL_THRESHOLD ≤ m4 ⊦ [skip] ( # apebs1 = # wlar0 ∧ unique-sqns(apebs1) ∧ valid-global-sqn(apebs1, n) ∧ valid-wl(apebs1, wlar0) ∧ valid-eraseq(q0) ∧ valid-eraseq(wlar0, q0) ∧ valid-eraseq(apebs1, q0) ∧ bflipset-cons(bflipset, wlar0) ∧ valid-ebatbl(apebs1, wlar0, vols[v, vols[v][m, ⌜vtblpnum1⌝ ]], n0) ∧ valid-vtbl(apebs1, vols, wlar0, n0) ∧ ubi-io-inv(apebs1) ∧ ( vols = vols[v, vols[v][m, ⌜vtblpnum1⌝ ]] ∧ id(apebs1, apebs, mapped-pebs(vols[v, vols[v][m, ⌜vtblpnum1⌝ ]])) ∧ q0.lebrefs ⊆ q.lebrefs ++ (VTBL_VOLID × VTBL_LNUM) ∨ (∃ v0, m0, n. v0 ∈ vols ∧ m0 < # vols[v0] ∧ vols[v0][m0] ≠ unmapped ∧ vols[v, vols[v][m, ⌜vtblpnum1⌝ ]] = vols[v0, vols[v0][m0, ⌜n⌝ ]] ∧ id(apebs1, apebs, mapped-pebs(vols) -- vols[v0][m0].pnum) ∧ apebs1[n].data = apebs[vols[v0][m0].pnum].data ∧ apebs1[n].fill ≤ apebs[vols[v0][m0].pnum].fill ∧ q0.lebrefs ⊆ q.lebrefs ++ (v0 × m0))) → err = ESUCCESS → Δ wlar0 < Δ wlar), err = ESUCCESS, m0 = 0, vtblpnum1 = vtblpnum2, vtblpnum2 = n2, VTBL_VOLID ∈ vols |