We are investigating a severe BLE extended-advertising discovery issue on an iPhone 17 running iOS 27.2 (24B119).
The phone fails to discover our peripherals approximately 90–95% of the time, based on our testing estimate. On rare occasions discovery succeeds, and the peripheral can then be connected.
We have filed FB25463740, with diagnostic captures and a comparison of successful and failing behavior.
Earlier iOS behavior
Extended-advertising discovery and connection worked without issues in our previous iOS 26 testing. Failures became apparent with iOS 27, with behavior varying by iPhone model. We do not have a verified iOS 26 baseline for this particular iPhone 17, so we are treating an OS regression as a possibility rather than a confirmed cause.
Test configuration
- Affected phone: iPhone 17, iOS 27.2 (24B119).
- Working comparison: iPhone 16, also running iOS 27.2 (24B119).
- Advertising: extended advertising with a 1M primary PHY, 2M secondary PHY, and 31-byte advertising data.
- Scanning: nRF Connect in the foreground, without a service UUID filter.
- Both phones were near the same powered-on peripherals, with advertising configuration unchanged during the comparison.
Observed behavior
- The iPhone 16 discovers the extended-advertising peripherals.
- The iPhone 17 usually does not, even while discovering other nearby BLE devices.
- Switching the peripherals to legacy advertising provides reliable discovery on the tested iPhone 17.
- When extended-advertising discovery does succeed, connection works.
- The issue reproduces in nRF Connect as well as our application.
What the captures show
During failing foreground scans, the iPhone 17 receives thousands of legacy advertising reports, but neither target peripheral appears in its HCI packet log.
A later capture contains rare successful extended-advertising receptions from both peripherals. These reports contain the same 31-byte payloads received by the working iPhone 16 and identify the secondary PHY as 2M. That capture also records a successful connection using 2M in both directions.
Successful and failing scans occur on the same iPhone 17 with identical checked scan-start command sequences. The commands complete successfully. This does not establish that all internal controller state is identical.
Wi-Fi disconnection preceded one successful period, but repeating that action did not reproduce success. We have not established Wi-Fi coexistence or primary-to-auxiliary timing as the cause.
Questions
Has anyone observed similar extended-advertising discovery failures on iPhone 17 or other models running iOS 27?
If so, which phone models, iOS builds, peripheral chipsets, and advertising PHYs are involved? Does legacy advertising remain reliable?
Are there any known issues or supported workarounds for this behavior? For Apple engineering, FB25463740 includes captures covering both successful and failing periods that may help distinguish reception, auxiliary-channel scheduling, and reporting/filtering problems.