Wireless CarPlay fails on Android 16 with Wi-Fi P2P security type UNKNOWN (-1) #20

Affected device and symptoms

• Samsung SM-S9280, Android 16 / API 36.
• USB CarPlay works, but wireless CarPlay repeatedly fails during Wi-Fi P2P hotspot startup.
• All 12 wireless startup attempts in the diagnostic log stop with:

Could not establish WIFI_P2P hotspot: Unsupported Wi-Fi P2P security type: -1

Wi-Fi is enabled and the required permissions are granted. A P2P group is created with usable credentials, but WheelPlay rejects its security report before reaching the Bluetooth / wireless handshake. The later P2P busy messages occur during cleanup.

Root cause

Android 16 added WifiP2pGroup.getSecurityType(). Some vendor frameworks return the documented SECURITY_TYPE_UNKNOWN (-1) even for the ordinary WPA2-PSK group created by the app. WheelPlay treats that value as unsupported and tears down the group. Before API 36, this code already assumes WPA2.

The same problem and fallback are documented in DiPlay #121. See also the Android API documentation.

Fix and verification

PR: #21 (based on the latest upstream main, 39485f9).

• Treat only SECURITY_TYPE_UNKNOWN as WPA2-PSK and emit a diagnostic.
• Preserve explicit WPA2 / WPA3 security reports and rejection of other unsupported values.
• Add Android 16 regression coverage for startup, credential preservation, explicit security modes, and failure cleanup.
• 45 related tests passed; release lint reports 0 errors and 4 existing warnings.
• The signed arm64 release was installed over the existing app on the affected SM-S9280. The reporter confirmed wireless CarPlay works after the fix.

Leaving this issue open for the PR to be reviewed and merged.