diff --git a/lib/gui/app/models/store.js b/lib/gui/app/models/store.js
index f4fc0fd0..24d34f66 100644
--- a/lib/gui/app/models/store.js
+++ b/lib/gui/app/models/store.js
@@ -24,6 +24,7 @@ const constraints = require('../../../shared/drive-constraints')
 const supportedFormats = require('../../../shared/supported-formats')
 const errors = require('../../../shared/errors')
 const fileExtensions = require('../../../shared/file-extensions')
+const utils = require('../../../shared/utils')
 const settings = require('./settings')
 
 /**
@@ -250,6 +251,20 @@ const storeReducer = (state = DEFAULT_STATE, action) => {
         })
       }
 
+      if (action.data.percentage !== undefined) {
+        if (!utils.isValidPercentage(action.data.percentage)) {
+          throw errors.createError({
+            title: `Invalid state percentage: ${action.data.percentage}`
+          })
+        }
+
+        if (!_.isNumber(action.data.eta)) {
+          throw errors.createError({
+            title: `Invalid state eta: ${action.data.eta}`
+          })
+        }
+      }
+
       return state.set('flashState', Immutable.fromJS(action.data))
     }
 
diff --git a/tests/gui/models/flash-state.spec.js b/tests/gui/models/flash-state.spec.js
index 6973cdb4..2650e75d 100644
--- a/tests/gui/models/flash-state.spec.js
+++ b/tests/gui/models/flash-state.spec.js
@@ -126,22 +126,6 @@ describe('Model: flashState', function () {
         }).to.not.throw('Missing flash fields: percentage')
       })
 
-      it('should throw if percentage is missing', function () {
-        flashState.setFlashingFlag()
-        m.chai.expect(function () {
-          flashState.setProgressState({
-            flashing: 2,
-            verifying: 0,
-            successful: 0,
-            failed: 0,
-            type: 'write',
-            eta: 15,
-            speed: 100000000000,
-            totalSpeed: 200000000000
-          })
-        }).to.throw('Missing flash fields: percentage')
-      })
-
       it('should throw if percentage is not a number', function () {
         flashState.setFlashingFlag()
         m.chai.expect(function () {
@@ -193,22 +177,6 @@ describe('Model: flashState', function () {
         }).to.throw('Invalid state percentage: -1')
       })
 
-      it('should throw if eta is missing', function () {
-        flashState.setFlashingFlag()
-        m.chai.expect(function () {
-          flashState.setProgressState({
-            flashing: 2,
-            verifying: 0,
-            successful: 0,
-            failed: 0,
-            type: 'write',
-            percentage: 50,
-            speed: 100000000000,
-            totalSpeed: 200000000000
-          })
-        }).to.throw('Missing flash fields: eta')
-      })
-
       it('should not throw if eta is equal to zero', function () {
         flashState.setFlashingFlag()
         m.chai.expect(function () {