diff --git a/src/components/structures/MatrixChat.tsx b/src/components/structures/MatrixChat.tsx
index 32d3bc7bd6..bbb1b77c9d 100644
--- a/src/components/structures/MatrixChat.tsx
+++ b/src/components/structures/MatrixChat.tsx
@@ -1707,9 +1707,10 @@ export default class MatrixChat extends React.PureComponent<IProps, IState> {
             }
         }
 
-        if (cli.getCrypto()) {
+        const crypto = cli.getCrypto();
+        if (crypto) {
             const blacklistEnabled = SettingsStore.getValueAt(SettingLevel.DEVICE, "blacklistUnverifiedDevices");
-            cli.setGlobalBlacklistUnverifiedDevices(blacklistEnabled);
+            crypto.globalBlacklistUnverifiedDevices = blacklistEnabled;
 
             // With cross-signing enabled, we send to unknown devices
             // without prompting. Any bad-device status the user should
diff --git a/src/components/views/settings/CryptographyPanel.tsx b/src/components/views/settings/CryptographyPanel.tsx
index 853a75e6b1..08917d215c 100644
--- a/src/components/views/settings/CryptographyPanel.tsx
+++ b/src/components/views/settings/CryptographyPanel.tsx
@@ -140,6 +140,7 @@ export default class CryptographyPanel extends React.Component<IProps, IState> {
     };
 
     private updateBlacklistDevicesFlag = (checked: boolean): void => {
-        MatrixClientPeg.safeGet().setGlobalBlacklistUnverifiedDevices(checked);
+        const crypto = MatrixClientPeg.safeGet().getCrypto();
+        if (crypto) crypto.globalBlacklistUnverifiedDevices = checked;
     };
 }
diff --git a/test/components/structures/MatrixChat-test.tsx b/test/components/structures/MatrixChat-test.tsx
index 4d1f78af97..432494b0e3 100644
--- a/test/components/structures/MatrixChat-test.tsx
+++ b/test/components/structures/MatrixChat-test.tsx
@@ -125,7 +125,6 @@ describe("<MatrixChat />", () => {
         }),
         getVisibleRooms: jest.fn().mockReturnValue([]),
         getRooms: jest.fn().mockReturnValue([]),
-        setGlobalBlacklistUnverifiedDevices: jest.fn(),
         setGlobalErrorOnUnknownDevices: jest.fn(),
         getCrypto: jest.fn().mockReturnValue({
             getVerificationRequestsToDeviceInProgress: jest.fn().mockReturnValue([]),
@@ -135,6 +134,7 @@ describe("<MatrixChat />", () => {
             getVersion: jest.fn().mockReturnValue("1"),
             setDeviceIsolationMode: jest.fn(),
             userHasCrossSigningKeys: jest.fn(),
+            globalBlacklistUnverifiedDevices: false,
         }),
         // This needs to not finish immediately because we need to test the screen appears
         bootstrapCrossSigning: jest.fn().mockImplementation(() => bootstrapDeferred.promise),