# "This reader is not supported" on Contactless & Chip reader

**URL:** <https://developer.squareup.com/forums/t/this-reader-is-not-supported-on-contactless-chip-reader/25562>\
**Category:** Questions\
**Created:** [March 13, 2026, 6:45am UTC](https://developer.squareup.com/forums/t/this-reader-is-not-supported-on-contactless-chip-reader/25562 "2026-03-13T06:45:53Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![jamescjl](https://avatars.discourse-cdn.com/v4/letter/j/7cd45c/32.png) [@jamescjl](https://developer.squareup.com/forums/u/jamescjl)\
**Post date:** [March 13, 2026, 6:45am UTC](https://developer.squareup.com/forums/t/this-reader-is-not-supported-on-contactless-chip-reader/25562/1 "2026-03-13T06:45:53Z")

</div>

**Environment:**

- Mobile Payments SDK version: 2.4.0 (Android)

- Android API: 34 (targetSdk), compileSdk 35, minSdk 28

- Device: RK3566 tablet (GMS certified, Google Play Store + Play Services installed)

- Reader: Square Reader for Contactless & Chip (2nd generation)

- Reader firmware: 411092

- App package: com.golfmark.express (production, not sandbox)

- Application ID: starts with sq0idp- (production credentials)

- SHA-256 fingerprint: registered in Square Developer Dashboard

**Issue:**  
After pairing a Square Reader via Bluetooth, the SDK’s built-in Settings UI shows:

> _ **Reader unavailable**  
> This reader is not supported. Try again with a supported reader._

The reader IS connected — battery level, firmware version, and serial number are all visible. The Bluetooth pairing succeeds, but the SDK rejects the reader as “not supported.”

**What works:**

- The official Square POS app on the **same tablet** pairs with the **same reader** and processes payments successfully

- The reader is a 2nd generation Contactless & Chip reader (S222) which is listed as supported

- SDK authorization succeeds (authorizationState.isAuthorized = true)

- SDK environment is PRODUCTION (not sandbox)

- All permissions granted (Bluetooth, Location, Phone State, Microphone)

**What I’ve tried:**

- SDK versions 2.3.0 and 2.4.0 — both show the same error

- Verified SHA-256 fingerprint matches Square Developer Dashboard registration

- Confirmed production Application ID (sq0idp-…) and production access token

- Verified device is not rooted (release-keys, verified boot green)

- Developer Options is disabled

- Completely uninstalled and reinstalled the app

- Forgot and re-paired the reader

**Timeline:**

- The same APK + reader combination **worked** on March 6 and successfully charged

- After flashing the updated GMS firmware and updating Google Play Services, the reader now shows “not supported.”

- Even reinstalling the previously-working APK now produces the same error

**Questions:**

1. What does “This reader is not supported” specifically mean in the SDK’s built-in Settings UI? Is this a device compatibility check, reader firmware check, or backend validation?

2. Is there a way to get the exact `ReaderUnavailable.reason` code behind this message?

3. Are there known device attestation / Play Integrity requirements that could cause this on a GMS-certified non-Samsung/Pixel device?

4. Does the reader firmware (411092) need to be updated to work with SDK 2.4.0? If so, how — since the SDK settings screen doesn’t offer an update option?

Any help would be appreciated. The official Square POS app works perfectly on this device, so I believe the hardware is compatible — something in the SDK’s validation is rejecting the reader.

---

<div class="post-metadata">

**Author:** ![Square-Dev-AI](https://sea1.discourse-cdn.com/square/forums/user_avatar/developer.squareup.com/square-dev-ai/32/2513_2.png) [@Square-Dev-AI](https://developer.squareup.com/forums/u/Square-Dev-AI)\
**Post date:** [March 13, 2026, 6:46am UTC](https://developer.squareup.com/forums/t/this-reader-is-not-supported-on-contactless-chip-reader/25562/2 "2026-03-13T06:46:07Z")

</div>

👋 I’m Square Dev AI, here to help answer your question!  
Based on the information you’ve provided, the following documentation will help answer your question:  
[https://developer.squareup.com/docs/reader-sdk/build-on-android](https://developer.squareup.com/docs/reader-sdk/build-on-android)

> **[Pair and Manage Card Readers](https://developer.squareup.com/docs/mobile-payments-sdk/android/pair-manage-readers)**
>
> Learn how to pair and manage card readers with the Mobile Payments SDK for Android.

> **Additional Documentation**
>
> [https://developer.squareup.com/docs/reader-sdk/what-it-does](https://developer.squareup.com/docs/reader-sdk/what-it-does)  
> [https://developer.squareup.com/docs/reader-sdk/cookbook/contactless-reader](https://developer.squareup.com/docs/reader-sdk/cookbook/contactless-reader)  
> [Mobile Payments SDK](https://developer.squareup.com/docs/mobile-payments-sdk)

If this documentation helped you find a solution, please check the box indicating that this reply solves the problem.  
Otherwise one of our Developer Advocates will provide additional assistance shortly.