diff --git a/src/mp-instance.js b/src/mp-instance.js
index eed6fa9e..fd678a65 100644
--- a/src/mp-instance.js
+++ b/src/mp-instance.js
@@ -86,6 +86,9 @@ export default function mParticleInstance(instanceName) {
     this._Identity = new Identity(this);
     this.Identity = this._Identity.IdentityAPI;
     this.generateHash = this._Helpers.generateHash;
+
+    // https://go.mparticle.com/work/SQDSDKS-6289
+    // TODO: Replace this with Store once Store is moved earlier in the init process
     this.getDeviceId = this._Persistence.getDeviceId;
 
     if (typeof window !== 'undefined') {
diff --git a/src/store.ts b/src/store.ts
index 892a8d6e..fbe936e2 100644
--- a/src/store.ts
+++ b/src/store.ts
@@ -162,6 +162,14 @@ export interface IStore {
     integrationDelayTimeoutStart: number; // UNIX Timestamp
     webviewBridgeEnabled?: boolean;
     wrapperSDKInfo: WrapperSDKInfo;
+
+    persistenceData?: IPersistenceMinified;
+
+    getDeviceId?(): string;
+    setDeviceId?(deviceId: string): void;
+
+    getAllUserAttributes?(mpid: MPID): Dictionary;
+    setUserAttributes?(mpid: MPID, userAttributes: Dictionary): void;
 }
 
 // TODO: Merge this with SDKStoreApi in sdkRuntimeModels
@@ -214,6 +222,27 @@ export default function Store(
             version: null,
             isInfoSet: false,
         },
+
+        // Placeholder for in-memory persistence model
+        persistenceData: {
+            cu: null,
+            gs: {
+                sid: null,
+                ie: null,
+                sa: null,
+                ss: null,
+                dt: null,
+                av: null,
+                cgid: null,
+                das: null,
+                ia: null,
+                c: null,
+                csm: null,
+                les: null,
+                ssd: null,
+            },
+            l: null,
+        },
     };
 
     for (var key in defaultStore) {
@@ -418,6 +447,14 @@ export default function Store(
             }
         }
     }
+
+    this.getDeviceId = () => this.deviceId;
+    this.setDeviceId = (deviceId: string) => {
+        this.deviceId = deviceId;
+        this.persistenceData.gs.das = deviceId;
+
+        mpInstance._Persistence.savePersistence(this.persistenceData);
+    };
 }
 
 export function processFlags(
@@ -527,4 +564,4 @@ function processDirectBaseUrls(
     }
 
     return directBaseUrls;
-}
\ No newline at end of file
+}
diff --git a/test/src/tests-store.ts b/test/src/tests-store.ts
index 584fb538..4f0ad4ec 100644
--- a/test/src/tests-store.ts
+++ b/test/src/tests-store.ts
@@ -248,6 +248,46 @@ describe('Store', () => {
         });
     });
 
+    describe('#getDeviceId', () => {
+        it('should return the deviceId from the store', () => {
+            const store: IStore = new Store(
+                sampleConfig,
+                window.mParticle.getInstance()
+            );
+
+            store.deviceId = 'foo';
+
+            expect(store.getDeviceId()).to.equal('foo');
+        });
+    });
+
+    describe('#setDeviceId', () => {
+        it('should set the deviceId in the store', () => {
+            const store: IStore = new Store(
+                sampleConfig,
+                window.mParticle.getInstance()
+            );
+
+            store.setDeviceId('foo');
+            expect(store.deviceId).to.equal('foo');
+        });
+
+        it('should set the deviceId in persistence', () => {
+            // Since this relies on persistence, we need to make sure
+            // we are using an mParticle instance that shares both
+            // store and persistence modules
+            const store = window.mParticle.getInstance()._Store;
+
+            store.setDeviceId('foo');
+            const fromPersistence = window.mParticle
+                .getInstance()
+                ._Persistence.getPersistence();
+
+            expect(store.deviceId).to.equal('foo');
+            expect(fromPersistence.gs.das).to.equal('foo');
+        });
+    });
+
     describe('#processFlags', () => {
         it('should return an empty object if no featureFlags are passed', () => {
             const flags = processFlags({} as SDKInitConfig, {} as SDKConfig);