diff --git a/dist/codecs/blockHeader.js b/dist/codecs/blockHeader.js
index 0675e59633a14c34148e90aa8c32bcfbc437330c..3cb9f47e889827d3b9d2c8490418176eda2d7590 100644
--- a/dist/codecs/blockHeader.js
+++ b/dist/codecs/blockHeader.js
@@ -1,4 +1,4 @@
-import { enhanceCodec, Bytes, _void } from 'scale-ts';
+import { enhanceCodec, Bytes, _void, u32 } from 'scale-ts';
 import '../utils/ss58-util.js';
 import './scale/Binary.js';
 import './scale/bitSequence.js';
@@ -33,7 +33,23 @@ const diggest = Variant(
   [0, 4, 5, 6, 8]
 );
 const hex32 = Hex(32);
-const blockHeader = Struct({
+
+// Quantus patch: this console serves two header layouts.
+//
+// `sp_runtime::generic::Header` encodes `number` with #[codec(compact)] and has
+// no field between `extrinsics_root` and `digest`. Quantus's `qp_header::Header`
+// does neither: `number` is a plain u32, and a `zk_tree_root: H256` sits before
+// the digest — deliberately, so the ZK root has a fixed offset in the header
+// preimage that miners cannot shift by manipulating the digest.
+//
+// Reading a Quantus header as a Substrate one consumes 2 bytes where 4 were
+// written; every field after shifts, and the digest vector eventually reads a
+// byte that is not a known DigestItem index. That surfaces three layers away as
+// `TypeError: innerDecoder is not a function`, papi retries the subfollow
+// forever, `runtime$` never emits, and the page renders nothing at all.
+//
+// See quantus/papi-console#4.
+const substrateHeader = Struct({
   parentHash: hex32,
   number: compactNumber,
   stateRoot: hex32,
@@ -41,5 +57,76 @@ const blockHeader = Struct({
   digests: Vector(diggest)
 });
 
+const quantusHeader = Struct({
+  parentHash: hex32,
+  number: u32,
+  stateRoot: hex32,
+  extrinsicRoot: hex32,
+  zkTreeRoot: hex32,
+  digests: Vector(diggest)
+});
+
+const asBytes = (input) =>
+  typeof input === "string"
+    ? Uint8Array.from(
+        input
+          .slice(2)
+          .match(/../g)
+          ?.map((b) => parseInt(b, 16)) ?? []
+      )
+    : input;
+
+const sameBytes = (a, b) =>
+  a.length === b.length && a.every((x, i) => x === b[i]);
+
+// Decide by round trip, not by guessing. A layout is right only if decoding and
+// re-encoding reproduces the input byte for byte — which also catches a short
+// read, trailing bytes, and a non-canonical compact. Trying the layouts in a
+// fixed order and taking the first that survives that check is deterministic;
+// picking one by inspecting a byte would not be.
+const decodeEitherLayout = (input) => {
+  // `archive.header$` in @polkadot-api/observable-client maps the RPC result
+  // straight through this decoder with no null check, and `archive_v1_header`
+  // answers `null` for any hash the node does not know. scale-ts then reaches
+  // `new DataView(null)`, which V8 reports as "First argument to DataView
+  // constructor must be an ArrayBuffer" and Firefox as "e is not an object" —
+  // neither of which mentions blocks, headers, or the node.
+  //
+  // It happens in bursts on a chain switch: the block list still holds the
+  // previous chain's hashes, and every one of them is unknown to the new node.
+  // Harmless, but it needs to say so.
+  if (input == null)
+    throw new Error("no block header: the node does not know this block");
+
+  const bytes = asBytes(input);
+  let firstError;
+
+  for (const codec of [substrateHeader, quantusHeader]) {
+    try {
+      const value = codec.dec(bytes);
+
+      if (sameBytes(codec.enc(value), bytes)) return value;
+    } catch (error) {
+      firstError ??= error;
+    }
+  }
+
+  throw firstError ?? new Error("block header matches no known layout");
+};
+
+// Keep every property the original codec carried and override only the decoder.
+// A scale-ts Struct exposes `inner` — its field codecs — and consumers reach for
+// it: this console's own block.state.ts does `blockHeader.inner.digests.inner`.
+// Replacing the codec with a bare [enc, dec] pair drops that, block.state.ts
+// throws while its module is evaluating, `createRoot().render()` never runs, and
+// the page is blank with no error on screen — the same symptom as the bug this
+// patch exists to fix, from the opposite cause.
+const blockHeader = Object.assign([], substrateHeader, {
+  0: substrateHeader.enc,
+  1: decodeEitherLayout,
+  enc: substrateHeader.enc,
+  dec: decodeEitherLayout
+});
+
 export { blockHeader };
 //# sourceMappingURL=blockHeader.js.map