diff --git a/src/index.js b/src/index.js
index a70da488..b5cae3ec 100755
--- a/src/index.js
+++ b/src/index.js
@@ -675,7 +675,7 @@ async function handleJavascriptPort(arg) {
     case "generateKeys": {
       const userLang = getUserLanguage();
       const [randomWords, hexRandomWords] = mnemonic.generateRandom(userLang);
-      const privateKey = ecc.seedPrivate(hexRandomWords);
+      const privateKey = mnemonic.seedPrivate(hexRandomWords);
       const publicKey = ecc.privateToPublic(privateKey);
 
       return {
@@ -690,7 +690,7 @@ async function handleJavascriptPort(arg) {
     }
     case "getAccountFrom12Words": {
       const { passphrase } = arg.data;
-      const privateKey = ecc.seedPrivate(mnemonic.toSeedHex(passphrase));
+      const privateKey = mnemonic.seedPrivate(mnemonic.toSeedHex(passphrase));
 
       if (!ecc.isValidPrivate(privateKey)) {
         return { error: "error.invalidKey" };
diff --git a/src/scripts/mnemonic.js b/src/scripts/mnemonic.js
index ef98bd3c..00f6ac6b 100755
--- a/src/scripts/mnemonic.js
+++ b/src/scripts/mnemonic.js
@@ -1,4 +1,6 @@
 import * as bip39 from 'bip39'
+import { sha256, PrivateKey } from 'eosjs/dist/eosjs-key-conversions'
+import { KeyType, privateKeyToString } from 'eosjs/dist/eosjs-numeric'
 
 /***
  * Generates a random mnemonic
@@ -28,6 +30,21 @@ function toSeedHex (mnemonic) {
   return bip39.mnemonicToSeedSync(mnemonic).toString('hex')
 }
 
+/**
+ * Derive an EOS private key from a seed string.
+ *
+ * Replaces ecc.seedPrivate, which is a no-op stub in eosjs-ecc-migration
+ * (it only logs "Method deprecated" and returns undefined). Reproduces the
+ * legacy eosjs-ecc behaviour exactly: PrivateKey(sha256(seed)), returned as a
+ * legacy WIF string, so keys match what existing accounts registered with.
+ * @param {string} seed
+ * @returns {string} legacy WIF private key
+ */
+function seedPrivate (seed) {
+  const data = Uint8Array.from(sha256(seed))
+  return PrivateKey.fromString(privateKeyToString({ type: KeyType.k1, data })).toLegacyString()
+}
+
 // =========================================
 // Exports
 // =========================================
@@ -35,4 +52,5 @@ function toSeedHex (mnemonic) {
 export default {
   generateRandom,
   toSeedHex,
+  seedPrivate,
 }