README.md

@@ -436,7 +436,11 @@ The core hierarchy is **Wallets → Addresses**:
       multi-address behavior as an HD wallet, including the "+" button and the
       address scan on import, but imported from an extended private key rather
       than a recovery phrase. It therefore has no recovery phrase to display or
-      back up.
+      back up. Only a master key may be imported; an xprv wallet already in
+      storage that was imported from a non-master key is detected from the depth
+      of its stored `xpub` by `src/shared/walletDefects.js`, explained in the
+      wallet list, and blocked from signing, sending and private-key export. It
+      is never deleted or rewritten.
 - An **address** holds ETH and ERC-20 tokens.
 - The user can have multiple wallets, each with multiple addresses (HD) or a
   single address (key).

TODO.md

@@ -44,6 +44,11 @@ undefined identifiers, which is how
 
 # Completed Steps
 
+- 2026-08-12: An xprv wallet already in storage that was imported from a
+  non-master key is detected from the depth of its stored `xpub`, explained in
+  the wallet list, and blocked from signing, sending and private-key export
+  instead of throwing on the send screen
+  ([#234](https://git.eeqj.de/sneak/AutistMask/issues/234)).
 - 2026-08-12: An unreported `holders_count` is now parsed as `null` rather than
   `0`, so the low-holder rule declines to judge an unknown count instead of
   hiding a legitimate token as spam, in both the transaction history and the

src/popup/views/addressDetail.js

@@ -29,6 +29,16 @@ const { log } = require("../../shared/log");
 const makeBlockie = require("ethereum-blockies-base64");
 const { decryptWithPassword } = require("../../shared/vault");
 const { getSignerForAddress } = require("../../shared/wallet");
+const { walletDefect } = require("../../shared/walletDefects");
+
+// The defect of the wallet the selected address belongs to, or null. Both the
+// send and the private-key export path check it before asking for a password,
+// so a wallet that cannot derive its keys says so instead of failing after the
+// user has typed one in.
+function selectedWalletDefect() {
+    if (state.selectedWallet === null) return null;
+    return walletDefect(state.wallets[state.selectedWallet]);
+}
 
 let ctx;
 
@@ -254,6 +264,11 @@ function init(_ctx) {
     });
 
     $("btn-send").addEventListener("click", () => {
+        const defect = selectedWalletDefect();
+        if (defect) {
+            showFlash(defect.shortMessage);
+            return;
+        }
         const addr =
             state.wallets[state.selectedWallet].addresses[
                 state.selectedAddress
@@ -298,6 +313,14 @@ function init(_ctx) {
     $("btn-export-privkey").addEventListener("click", () => {
         moreDropdown.classList.add("hidden");
         moreBtn.classList.remove("bg-fg", "text-bg");
+        // There is no private key to export for an address this wallet
+        // cannot derive. Without this the export screen would take a
+        // password and then report it as wrong.
+        const defect = selectedWalletDefect();
+        if (defect) {
+            showFlash(defect.shortMessage);
+            return;
+        }
         pushCurrentView();
         const wallet = state.wallets[state.selectedWallet];
         const addr = wallet.addresses[state.selectedAddress];

src/popup/views/addressToken.js

@@ -35,6 +35,7 @@ const {
 } = require("./send");
 const { log } = require("../../shared/log");
 const makeBlockie = require("ethereum-blockies-base64");
+const { walletDefect } = require("../../shared/walletDefects");
 
 let ctx;
 
@@ -338,6 +339,11 @@ function init(_ctx) {
     });
 
     $("btn-address-token-send").addEventListener("click", () => {
+        const defect = walletDefect(state.wallets[state.selectedWallet]);
+        if (defect) {
+            showFlash(defect.shortMessage);
+            return;
+        }
         const addr =
             state.wallets[state.selectedWallet].addresses[
                 state.selectedAddress

src/popup/views/approval.js

@@ -21,6 +21,7 @@ const { ERC20_ABI } = require("../../shared/constants");
 const { TOKEN_BY_ADDRESS } = require("../../shared/tokenList");
 const { decryptWithPassword } = require("../../shared/vault");
 const { getSignerForAddress } = require("../../shared/wallet");
+const { walletDefect } = require("../../shared/walletDefects");
 const { getProvider } = require("../../shared/balances");
 const txStatus = require("./txStatus");
 const uniswap = require("../../shared/uniswap");
@@ -280,6 +281,7 @@ function showTxApproval(details) {
 
     showView("approve-tx");
     attachCopyHandlers("view-approve-tx");
+    gateOnWalletDefect("approve-tx-error", "btn-approve-tx");
 }
 
 function decodeHexMessage(hex) {
@@ -379,6 +381,7 @@ function showSignApproval(details) {
 
     showView("approve-sign");
     attachCopyHandlers("view-approve-sign");
+    gateOnWalletDefect("approve-sign-error", "btn-approve-sign");
 }
 
 function show(id) {
@@ -431,6 +434,20 @@ function setSignButtonBusy(busy) {
     $("btn-approve-sign").classList.toggle("text-muted", busy);
 }
 
+// Say so on the approval screen itself, and disable the approve button, when
+// the active address belongs to a wallet whose keys cannot be derived. Without
+// this the screen would take a password and fail after deriving it. Reject
+// stays available; the wallet is not touched. Returns true when it gated.
+function gateOnWalletDefect(errorId, buttonId) {
+    const active = findActiveWallet();
+    const defect = active ? walletDefect(active.wallet) : null;
+    if (!defect) return false;
+    showError(errorId, defect.shortMessage);
+    $(buttonId).disabled = true;
+    $(buttonId).classList.add("text-muted");
+    return true;
+}
+
 // Locate the wallet and the address index owning the currently active
 // address. Returns null when no wallet holds it.
 function findActiveWallet() {
@@ -492,6 +509,14 @@ function init(ctx) {
             return;
         }
 
+        const defect = walletDefect(active.wallet);
+        if (defect) {
+            password = null;
+            showError("approve-tx-error", defect.shortMessage);
+            setTxButtonBusy(false);
+            return;
+        }
+
         // Decrypt here, in the popup. The password must never cross the
         // extension messaging boundary; only the signed transaction does.
         let decryptedSecret;
@@ -583,6 +608,14 @@ function init(ctx) {
             return;
         }
 
+        const defect = walletDefect(active.wallet);
+        if (defect) {
+            password = null;
+            showError("approve-sign-error", defect.shortMessage);
+            setSignButtonBusy(false);
+            return;
+        }
+
         // Decrypt here, in the popup. The password must never cross the
         // extension messaging boundary; only the signature does.
         let decryptedSecret;

src/popup/views/home.js

@@ -21,6 +21,10 @@ const {
     resetSendValidation,
 } = require("./send");
 const { deriveAddressFromXpub } = require("../../shared/wallet");
+const {
+    walletDefect,
+    walletDefectHtml,
+} = require("../../shared/walletDefects");
 const {
     formatUsd,
     getPrice,
@@ -214,25 +218,23 @@ async function loadHomeTxs(ctx) {
     }
 }
 
-function render(ctx) {
+// The wallet list markup. Pure: it reads state and returns a string, so the
-    const container = $("wallet-list");
+// list can be asserted on without a DOM.
-    if (state.wallets.length === 0) {
+function walletListHtml() {
-        container.innerHTML =
-            '<p class="text-muted py-2">No wallets yet. Add one to get started.</p>';
-        renderTotalValue();
-        renderActiveAddress();
-        return;
-    }
-
     let html = "";
     state.wallets.forEach((wallet, wi) => {
+        const defect = walletDefect(wallet);
         html += `<div>`;
         html += `<div class="flex justify-between items-center bg-section py-1 px-2" style="margin:0 -0.5rem">`;
         html += `<span class="font-bold cursor-pointer wallet-name underline decoration-dashed" data-wallet="${wi}">${wallet.name}</span>`;
-        if (wallet.type === "hd" || wallet.type === "xprv") {
+        // No "+" on a defective wallet: deriving another address from that
+        // xpub would only add one more address the key does not produce
+        // under the standard path.
+        if (!defect && (wallet.type === "hd" || wallet.type === "xprv")) {
             html += `<button class="btn-add-address border border-border px-1 hover:bg-fg hover:text-bg cursor-pointer text-xs" data-wallet="${wi}" title="Add another address to this wallet">+</button>`;
         }
         html += `</div>`;
+        html += walletDefectHtml(wallet);
 
         wallet.addresses.forEach((addr, ai) => {
             html += `<div class="address-row py-1 border-b border-border-light cursor-pointer hover:bg-hover" data-wallet="${wi}" data-address="${ai}">`;
@@ -260,7 +262,20 @@ function render(ctx) {
 
         html += `</div>`;
     });
-    container.innerHTML = html;
+    return html;
+}
+
+function render(ctx) {
+    const container = $("wallet-list");
+    if (state.wallets.length === 0) {
+        container.innerHTML =
+            '<p class="text-muted py-2">No wallets yet. Add one to get started.</p>';
+        renderTotalValue();
+        renderActiveAddress();
+        return;
+    }
+
+    container.innerHTML = walletListHtml();
 
     container.querySelectorAll(".address-row").forEach((row) => {
         row.addEventListener("click", async () => {
@@ -348,6 +363,13 @@ function render(ctx) {
     loadHomeTxs(ctx);
 }
 
+// The defect of the wallet the selected address belongs to, or null. Call
+// after selectActiveAddress().
+function selectedWalletDefect() {
+    if (state.selectedWallet === null) return null;
+    return walletDefect(state.wallets[state.selectedWallet]);
+}
+
 function selectActiveAddress() {
     for (let wi = 0; wi < state.wallets.length; wi++) {
         for (let ai = 0; ai < state.wallets[wi].addresses.length; ai++) {
@@ -371,6 +393,13 @@ function init(ctx) {
             showFlash("No active address selected.");
             return;
         }
+        // Before the balance check and before any password is asked for: this
+        // wallet cannot sign at all, so the send screen is a dead end.
+        const defect = selectedWalletDefect();
+        if (defect) {
+            showFlash(defect.shortMessage);
+            return;
+        }
         const addr = currentAddress();
         if (!addr.balance || parseFloat(addr.balance) === 0) {
             showFlash("Cannot send \u2014 zero balance.");
@@ -396,4 +425,4 @@ function init(ctx) {
     });
 }
 
-module.exports = { init, render };
+module.exports = { init, render, walletListHtml };

src/shared/wallet.js

@@ -120,9 +120,24 @@ function getSignerForAddress(walletData, addrIndex, decryptedSecret) {
         return node.deriveChild(addrIndex);
     }
     if (walletData.type === "xprv") {
-        const node =
+        // Checked here rather than through masterXprvOrThrow so the message
-            masterXprvOrThrow(decryptedSecret).derivePath(BIP44_ETH_PATH);
+        // fits the situation: nobody is importing anything at signing time,
-        return node.deriveChild(addrIndex);
+        // and this wallet is already in storage. src/shared/walletDefects.js
+        // catches it at list-render time; this is the backstop behind that.
+        const node = parseExtendedKey(decryptedSecret);
+        if (!node || !node.privateKey) {
+            throw new Error(
+                "This wallet's stored key is not a valid extended private " +
+                    "key, so it cannot sign.",
+            );
+        }
+        if (node.depth !== MASTER_DEPTH) {
+            throw new Error(
+                "This wallet was imported from an extended private key that " +
+                    "is not a master key, so it cannot sign.",
+            );
+        }
+        return node.derivePath(BIP44_ETH_PATH).deriveChild(addrIndex);
     }
     return new Wallet(decryptedSecret);
 }
@@ -142,6 +157,7 @@ function walletHasRecoveryPhrase(walletData) {
 
 module.exports = {
     generateMnemonic,
+    parseExtendedKey,
     deriveAddressFromXpub,
     hdWalletFromMnemonic,
     hdWalletFromXprv,

src/shared/walletDefects.js

@@ -0,0 +1,86 @@
+// Wallets already in stored state whose key cannot be used, and the copy that
+// explains them.
+//
+// Refusing a non-master extended private key at import time does nothing for a
+// wallet imported before that refusal existed. Such a wallet is detected here,
+// at wallet-list render time, so the user meets the explanation on the list
+// screen rather than an exception on the send screen. Nothing here modifies or
+// removes a wallet: the record is the user's data.
+
+const { parseExtendedKey } = require("./wallet");
+
+const NON_MASTER_XPRV = "non-master-xprv";
+
+// An "xprv" wallet stores the neutered BIP-44 Ethereum node, four levels below
+// the key that was imported: the current import path derives the absolute
+// m/44'/60'/0'/0 from a depth-0 key, and the pre-#210 path derived the same
+// four levels as a relative path beneath whatever depth it was given. A master
+// import therefore stores a depth-4 xpub and a depth-d import stores depth
+// d + 4, which makes the stored xpub an exact read on the imported key's
+// depth — and it is readable without the password, unlike the key itself.
+const BIP44_ETH_XPUB_DEPTH = 4;
+
+const DEFECTS = {
+    [NON_MASTER_XPRV]: {
+        id: NON_MASTER_XPRV,
+        heading: "This wallet's addresses were derived incorrectly.",
+        paragraphs: [
+            "This wallet was imported from an extended private key that is " +
+                "not a master key. An earlier version applied the Ethereum " +
+                "derivation path beneath that key instead of from a master " +
+                "key, so the addresses listed here are not the ones that key " +
+                "produces under the standard path.",
+            "Signing and sending are disabled for this wallet. The addresses " +
+                "do descend from the extended private key you imported, so " +
+                "anything they hold is still reachable by software that " +
+                "repeats the same non-standard derivation. Check them in a " +
+                "block explorer before deciding what to do.",
+            "To see the addresses this key produces under the standard path, " +
+                "import the master extended private key, or the recovery " +
+                "phrase it came from, as a new wallet. Nothing here has been " +
+                "changed or removed, and this wallet stays until you delete " +
+                "it yourself.",
+        ],
+        // One sentence for the places that have room for one: the flash on a
+        // blocked Send, the inline error on the approval screens.
+        shortMessage:
+            "This wallet cannot sign, because it was imported from an " +
+            "extended private key that is not a master key. The wallet list " +
+            "explains what happened.",
+    },
+};
+
+// The defect record for a wallet, or null if there is nothing wrong with it
+// that this module can see. Read-only.
+//
+// A wallet whose xpub will not parse gets null rather than a defect: there is
+// no basis in that case to tell the user their key was not a master key, and a
+// wrong explanation is worse than none.
+function walletDefect(walletData) {
+    if (!walletData || walletData.type !== "xprv") return null;
+    const node = parseExtendedKey(walletData.xpub);
+    if (!node) return null;
+    if (node.depth === BIP44_ETH_XPUB_DEPTH) return null;
+    return DEFECTS[NON_MASTER_XPRV];
+}
+
+// The notice block for the wallet list, or "" for a wallet with no defect.
+// The copy is fixed text from this module, so it needs no escaping.
+function walletDefectHtml(walletData) {
+    const defect = walletDefect(walletData);
+    if (!defect) return "";
+    let html =
+        '<div class="border border-red-500 border-dashed p-2 my-1 text-xs text-red-500">';
+    html += `<div class="font-bold mb-1">${defect.heading}</div>`;
+    for (const p of defect.paragraphs) {
+        html += `<p class="mb-1">${p}</p>`;
+    }
+    html += "</div>";
+    return html;
+}
+
+module.exports = {
+    NON_MASTER_XPRV,
+    walletDefect,
+    walletDefectHtml,
+};

tests/walletDefects.test.js

@@ -0,0 +1,290 @@
+// Tests for the stored-state half of the non-master extended key problem.
+//
+// Refusing a non-master xprv at import time does nothing for a wallet that is
+// already in storage: the import that created it ran before the refusal
+// existed. Such a wallet used to sign for the wrong tree and now throws on the
+// send screen instead. These tests pin down that it is named and explained in
+// the wallet list, that nothing on the way there throws, and that a wallet
+// imported from a real master key is untouched by any of it.
+
+const { HDNodeWallet, Mnemonic } = require("ethers");
+
+const wallet = require("../src/shared/wallet");
+const {
+    walletDefect,
+    walletDefectHtml,
+    NON_MASTER_XPRV,
+} = require("../src/shared/walletDefects");
+
+// BIP-39 test vector phrase, published; never used for real funds.
+const VECTOR_PHRASE =
+    "test test test test test test test test test test test junk";
+
+function seedNode(phrase) {
+    return HDNodeWallet.fromSeed(Mnemonic.fromPhrase(phrase, "").computeSeed());
+}
+
+// The master (depth-0) key, which is what the import flow accepts today.
+function masterXprv(phrase) {
+    return seedNode(phrase).extendedKey;
+}
+
+// The account-level (depth-3) key m/44'/60'/0'. A normal thing for a user to
+// hold, and what the import flow used to accept.
+function accountXprv(phrase) {
+    return seedNode(phrase).derivePath("m/44'/60'/0'").extendedKey;
+}
+
+// The wallet record the CURRENT import path writes for a master key: the
+// neutered m/44'/60'/0'/0 node, four levels below a depth-0 key.
+function healthyXprvWallet(name = "Master") {
+    const { xpub, firstAddress } = wallet.hdWalletFromXprv(
+        masterXprv(VECTOR_PHRASE),
+    );
+    return {
+        name,
+        type: "xprv",
+        xpub,
+        nextIndex: 1,
+        encryptedSecret: "irrelevant-to-these-tests",
+        addresses: [{ address: firstAddress, balance: "0.0000" }],
+    };
+}
+
+// The wallet record the PRE-#210 import path wrote for an account-level key:
+// the same four levels, but derived as a relative path *beneath* the key, so
+// the stored xpub sits at depth 3 + 4 = 7. Built here the way the old code
+// built it rather than by calling the module under test, which now refuses.
+function brokenXprvWallet(name = "Imported xprv") {
+    const node = HDNodeWallet.fromExtendedKey(
+        accountXprv(VECTOR_PHRASE),
+    ).derivePath("44'/60'/0'/0");
+    return {
+        name,
+        type: "xprv",
+        xpub: node.neuter().extendedKey,
+        nextIndex: 1,
+        encryptedSecret: "irrelevant-to-these-tests",
+        addresses: [
+            { address: node.deriveChild(0).address, balance: "0.0000" },
+        ],
+    };
+}
+
+describe("the fixtures are what the two import paths actually produced", () => {
+    test("a master import stores a depth-4 xpub", () => {
+        expect(
+            HDNodeWallet.fromExtendedKey(healthyXprvWallet().xpub).depth,
+        ).toBe(4);
+    });
+
+    test("the pre-fix account-level import stored a depth-7 xpub", () => {
+        expect(
+            HDNodeWallet.fromExtendedKey(brokenXprvWallet().xpub).depth,
+        ).toBe(7);
+    });
+});
+
+describe("walletDefect", () => {
+    test("names the defect on a stored non-master xprv wallet", () => {
+        const defect = walletDefect(brokenXprvWallet());
+
+        expect(defect).not.toBeNull();
+        expect(defect.id).toBe(NON_MASTER_XPRV);
+    });
+
+    test("a depth-0 xprv wallet has no defect", () => {
+        expect(walletDefect(healthyXprvWallet())).toBeNull();
+    });
+
+    test("hd and key wallets are never assessed", () => {
+        expect(
+            walletDefect({ type: "hd", xpub: brokenXprvWallet().xpub }),
+        ).toBe(null);
+        expect(walletDefect({ type: "key" })).toBeNull();
+    });
+
+    test("an xprv wallet whose xpub cannot be parsed makes no claim", () => {
+        // No basis to say the key was non-master, so nothing is asserted
+        // about it rather than guessing.
+        expect(walletDefect({ type: "xprv", xpub: "not-a-key" })).toBeNull();
+        expect(walletDefect({ type: "xprv" })).toBeNull();
+    });
+
+    test("nothing about the wallet record is modified by the check", () => {
+        const w = brokenXprvWallet();
+        const before = JSON.stringify(w);
+
+        walletDefect(w);
+
+        expect(JSON.stringify(w)).toBe(before);
+    });
+});
+
+describe("the explanatory copy", () => {
+    const defect = walletDefect(brokenXprvWallet());
+
+    test("every sentence of it is a full sentence", () => {
+        for (const text of [defect.heading, ...defect.paragraphs]) {
+            expect(text).toMatch(/^[A-Z]/);
+            expect(text.trimEnd()).toMatch(/\.$/);
+        }
+    });
+
+    test("it says what was derived wrongly and that these are not the standard addresses", () => {
+        const body = defect.paragraphs.join(" ");
+
+        expect(body).toContain("not a master key");
+        expect(body).toMatch(/standard path/);
+    });
+
+    test("it does not claim the funds are safe and does not claim a loss", () => {
+        const all = [defect.heading, ...defect.paragraphs].join(" ");
+
+        expect(all).not.toMatch(/\bsafe\b/i);
+        expect(all).not.toMatch(/\blost\b|\bstolen\b|\bgone\b/i);
+    });
+
+    test("it says the wallet is not deleted and what the user can do", () => {
+        const body = defect.paragraphs.join(" ");
+
+        expect(body).toMatch(/until you delete it yourself/);
+        expect(body).toMatch(/recovery phrase/);
+    });
+
+    test("it uses the project's vocabulary", () => {
+        const all = [
+            defect.heading,
+            ...defect.paragraphs,
+            defect.shortMessage,
+        ].join(" ");
+
+        expect(all).not.toMatch(/seed phrase|mnemonic|passphrase/i);
+        expect(all).not.toMatch(/\baccounts?\b/i);
+    });
+});
+
+describe("walletDefectHtml", () => {
+    test("renders the heading and every paragraph for a defective wallet", () => {
+        const defect = walletDefect(brokenXprvWallet());
+        const html = walletDefectHtml(brokenXprvWallet());
+
+        expect(html).toContain(defect.heading);
+        for (const p of defect.paragraphs) {
+            expect(html).toContain(p);
+        }
+    });
+
+    test("renders nothing at all for a healthy wallet", () => {
+        expect(walletDefectHtml(healthyXprvWallet())).toBe("");
+    });
+});
+
+describe("the wallet list", () => {
+    let home;
+    let state;
+
+    beforeAll(() => {
+        global.chrome = {
+            storage: { local: { get: async () => ({}), set: async () => {} } },
+            runtime: { sendMessage: () => {} },
+        };
+        home = require("../src/popup/views/home");
+        state = require("../src/shared/state").state;
+    });
+
+    afterEach(() => {
+        state.wallets = [];
+        state.activeAddress = null;
+    });
+
+    test("a stored depth-3 xprv wallet renders the explanation", () => {
+        state.wallets = [brokenXprvWallet("Imported xprv")];
+
+        const html = home.walletListHtml();
+
+        expect(html).toContain(walletDefect(state.wallets[0]).heading);
+        expect(html).toContain("Imported xprv");
+    });
+
+    test("it does not offer to derive further addresses from that wallet", () => {
+        state.wallets = [brokenXprvWallet()];
+
+        expect(home.walletListHtml()).not.toContain("btn-add-address");
+    });
+
+    test("a normal depth-0 xprv wallet renders exactly as it did before", () => {
+        state.wallets = [healthyXprvWallet("Master")];
+
+        const html = home.walletListHtml();
+
+        expect(html).not.toContain(walletDefect(brokenXprvWallet()).heading);
+        expect(html).toContain("btn-add-address");
+        expect(html).toContain(state.wallets[0].addresses[0].address);
+    });
+
+    test("the defective wallet's notice does not bleed onto a healthy one", () => {
+        state.wallets = [brokenXprvWallet("Broken"), healthyXprvWallet("Fine")];
+
+        const html = home.walletListHtml();
+        const healthyPart = html.slice(html.indexOf("Fine"));
+
+        expect(html).toContain(walletDefect(state.wallets[0]).heading);
+        expect(healthyPart).not.toContain(
+            walletDefect(state.wallets[0]).heading,
+        );
+        expect(healthyPart).toContain("btn-add-address");
+    });
+});
+
+describe("no path throws an unhandled error for a defective wallet", () => {
+    test("address derivation from the stored xpub still works", () => {
+        // The stored xpub is at a non-standard depth but is a valid extended
+        // key; deriving from it is what the list render already does.
+        const w = brokenXprvWallet();
+
+        expect(() => wallet.deriveAddressFromXpub(w.xpub, 0)).not.toThrow();
+        expect(wallet.deriveAddressFromXpub(w.xpub, 0)).toBe(
+            w.addresses[0].address,
+        );
+    });
+
+    test("the wallet list renders without throwing", () => {
+        const { state } = require("../src/shared/state");
+        const home = require("../src/popup/views/home");
+        state.wallets = [brokenXprvWallet()];
+
+        expect(() => home.walletListHtml()).not.toThrow();
+
+        state.wallets = [];
+    });
+
+    test("signing refuses with the named defect rather than a bare failure", () => {
+        // getSignerForAddress is the backstop behind the UI gate. It must
+        // still refuse, and it must say why in a sentence the user can read.
+        let thrown = null;
+        try {
+            wallet.getSignerForAddress(
+                { type: "xprv" },
+                0,
+                accountXprv(VECTOR_PHRASE),
+            );
+        } catch (e) {
+            thrown = e;
+        }
+
+        expect(thrown).not.toBeNull();
+        expect(thrown.message).toMatch(/master key/);
+        expect(thrown.message.trimEnd()).toMatch(/\.$/);
+    });
+
+    test("a healthy xprv wallet signs as it always did", () => {
+        const signer = wallet.getSignerForAddress(
+            { type: "xprv" },
+            0,
+            masterXprv(VECTOR_PHRASE),
+        );
+
+        expect(signer.address).toBe(healthyXprvWallet().addresses[0].address);
+    });
+});