diff --git a/CHANGELOG.md b/CHANGELOG.md
index 4a0a1f80f..73b564ab8 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,6 +2,9 @@
 
 ## Unreleased
 
+- fixed: Allow duplicate sync keys when performing a wallet split, in case a previous failed attempt left a repo behind.
+- fixed: Do not lose wallet import history when doing a split-archive-split.
+
 ## 2.38.3 (2026-01-06)
 
 - added: Added `change2.edge.app` server to default change server list.
diff --git a/src/core/fake/fake-server.ts b/src/core/fake/fake-server.ts
index f0397dce1..b3e5de2ad 100644
--- a/src/core/fake/fake-server.ts
+++ b/src/core/fake/fake-server.ts
@@ -275,6 +275,7 @@ function createLogin(request: ApiRequest, login?: DbLogin): HttpResponse {
 
   // Set up repos:
   const keys = asMaybe(asCreateKeysPayload, () => ({
+    allowExisting: false,
     newSyncKeys: [],
     keyBoxes: []
   }))(body.data)
diff --git a/src/core/login/keys.ts b/src/core/login/keys.ts
index 9b7b2db63..a18c91161 100644
--- a/src/core/login/keys.ts
+++ b/src/core/login/keys.ts
@@ -67,11 +67,15 @@ export function makeKeyInfo(
 
 /**
  * Assembles all the resources needed to attach new keys to the account.
+ * @param allowExisting True if the sync keys were derived deterministically,
+ * which implies that duplicate sync keys on the server are not errors,
+ * but leftovers from an earlier failed splitting attempt.
  */
 export function makeKeysKit(
   ai: ApiInput,
   sessionKey: SessionKey,
-  keyInfos: EdgeWalletInfo[]
+  keyInfos: EdgeWalletInfo[],
+  allowExisting: boolean = false
 ): LoginKit {
   // For crash errors:
   ai.props.log.breadcrumb('makeKeysKit', {})
@@ -95,7 +99,7 @@ export function makeKeysKit(
 
   return {
     loginId: sessionKey.loginId,
-    server: wasCreateKeysPayload({ keyBoxes, newSyncKeys }),
+    server: wasCreateKeysPayload({ allowExisting, keyBoxes, newSyncKeys }),
     serverPath: '/v2/login/keys',
     stash: { keyBoxes }
   }
diff --git a/src/core/login/splitting.ts b/src/core/login/splitting.ts
index 957b1ad36..aefc7a3a0 100644
--- a/src/core/login/splitting.ts
+++ b/src/core/login/splitting.ts
@@ -147,7 +147,7 @@ export async function splitWalletInfo(
       walletInfos[newWalletInfo.id] = {
         archived: false,
         deleted: false,
-        migratedFromWalletId: undefined
+        migratedFromWalletId: existingWalletInfo.migratedFromWalletId
       }
       await changeWalletStates(ai, accountId, walletInfos)
       return newWalletInfo.id
@@ -157,7 +157,7 @@ export async function splitWalletInfo(
   }
 
   // Add the keys to the login:
-  const kit = makeKeysKit(ai, sessionKey, [newWalletInfo])
+  const kit = makeKeysKit(ai, sessionKey, [newWalletInfo], true)
   await applyKit(ai, sessionKey, kit)
 
   // Try to copy metadata on a best-effort basis.
diff --git a/src/types/server-cleaners.ts b/src/types/server-cleaners.ts
index e135c8c9d..84db52cd8 100644
--- a/src/types/server-cleaners.ts
+++ b/src/types/server-cleaners.ts
@@ -245,6 +245,7 @@ export const asChangeVouchersPayload: Cleaner<ChangeVouchersPayload> = asObject(
 )
 
 export const asCreateKeysPayload: Cleaner<CreateKeysPayload> = asObject({
+  allowExisting: asOptional(asBoolean, false),
   keyBoxes: asArray(asEdgeBox),
   newSyncKeys: asOptional(asArray(asString), () => [])
 })
diff --git a/src/types/server-types.ts b/src/types/server-types.ts
index eaed80a88..885c7a406 100644
--- a/src/types/server-types.ts
+++ b/src/types/server-types.ts
@@ -168,6 +168,7 @@ export interface ChangeVouchersPayload {
 }
 
 export interface CreateKeysPayload {
+  allowExisting: boolean
   keyBoxes: EdgeBox[]
   newSyncKeys: string[]
 }