BLE LE Privacy Issue with iPad A16 (11th Gen?) – Peripheral Not Responding After MTU Exchange

App & System Services Core OS
drumStick
drumStick OP
Created 2w
Replies 3
Boosts 0
Views 53
Participants 2

Hi all,

I'm encountering a BLE issue with the newer iPad models featuring the A16 Bionic chip (e.g., iPad 11th Gen). I have an iOS application that runs as a BLE peripheral, and it used to work flawlessly with various central devices.

📱 Device Specs

  • Model: iPad (A16 Bionic)

  • OS: iPadOS 18.6

✅ Working Setup (Before):

  • iOS app acts as a BLE peripheral (advertises a custom service).
  • Central device (Windows/Linux/Android) could:
    • Discover advertisements
    • Connect to the peripheral
    • Exchange MTU
    • Discover GATT services
    • Communicate bidirectionally

❌ Issue with iPad A16 (Newer Devices):

  • Central device receives advertisements and connects.

  • MTU exchange request is sent by central, but iPad A16 does not respond.

  • The BLE link remains active but only transmits empty PDUs, and communication never proceeds.

  • Same issue observed with third-party apps like BLE HID keyboard — they also fail to connect or communicate on A16 iPads but work on older devices (e.g., iPad 10th Gen and below).

🔍 Debugging So Far:

  • Confirmed that MTU Exchange Request is compliant (Client Rx MTU = 527).

  • Works fine with iPad 10th Gen and earlier.

  • Works with Android, Windows, and even Linux central stacks with older iPads.

  • A16-based iPads seem to silently drop or ignore the MTU request.

🧪 Suspected Cause:

  • Possible regression or behavioral change in LE Privacy handling on newer iPads.

  • Possibly tied to iPadOS version or Bluetooth controller firmware.

🙏 Looking for:

  • Anyone else facing similar BLE issues on iPads with A16?

  • Any known changes to BLE LE Privacy, MTU negotiation, or connection behavior in iPadOS on A16 devices?

  • Any workarounds, entitlements, or configuration changes that fixed the issue?

Would appreciate any insights or suggestions. Thank you!

Replies  3
Boosts  0
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Apple Staff, Engineer
Engineer OP
Apple
2w

Our engineering teams need to investigate this issue.

We'd greatly appreciate it if you could open a bug report, include crash logs and sample code or models that reproduce the issue, and post the FB number here once you do.

We also need packet logs if you can, and a diagnostic log from the iPad in question.

Please go to https://developer.apple.com/bug-reporting/profiles-and-logs/ and follow the instructions for Bluetooth for iOS to install a logging profile on your device. Then reproduce the issue, and follow the instructions at the above link to create a sysdiagnose. And attach that to the Feedback report as well.

Bug Reporting: How and Why? has tips on creating a successful bug report.

Please @ mention me in your response with the Feedback number so I can route it to the appropriate teams without delay.

Argun Tekant /  DTS Engineer / Core Technologies

1
drumStick
drumStick OP
1w

@Engineer

  • Feedback report filed: FB19543059

Attached:

  • sysdiagnose,
  • WireShark sniffed packet logs,
  • and link for peripheral app used on iPad as requested.

Let me know if anything else is required.

0
Apple Staff, Engineer
Engineer OP
Apple
1w

@drumStick Thank you for the report and the logs. They are very helpful

We would like to ask you for additional very specific diagnostic log for this. If you can, please open a support request at https://developer.apple.com/contact/request/code-level-support/ and reference this forum thread and my name in the "Did someone from Apple ask you to submit ..." section.

I'll be on the lookout for it, and I will send you the instructions for those logs.

Argun Tekant /  DTS Engineer / Core Technologies

1
BLE LE Privacy Issue with iPad A16 (11th Gen?) – Peripheral Not Responding After MTU Exchange
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