Ad-hoc wifi issues iOS 14 iPhone 11 and 12

Question

Created Dec ’20

Replies 4

Boosts 0

Views 2.2k

Participants 2

We've had a an app that connects to a device via ad-hoc wifi for several years now, covering many iOS versions and devices.

Now, we have connection issues.

Symptoms: connects to the network provided by the device, but times out when connecting (TCP) to its port 35000.
The app retries, but fails. Repeat ad nauseam.

We're up-to-date with the location permission required by iOS 13 (for SSID access), and the 'Local Network' permission requirement imposed by iOS14. The permission popup for the latter is shown and OK'd.
The network provided by the device is open.

iPhone 8 / iOS 14.2: Ok
iPhone X / iOS 14.2: Ok
iPhone 11 / iOS 14.2: fails
iPhone 12 / iOS 14.2 fails.
iPhone 11 pre iOS 14.2: ok

Tried all the usual resetting exercises and switching off BT.
Tried Private Address off.

We have one (1) customer who through a combination of impatience (tried a good bit of all the usual on/off/reset stuff) and patience (left the app trying to reconnect for a long time) managed to establish the connection. We've been unable to reproduce this, unfortunately.

I have seen one developer suspecting hardware issues with and/or differences in the WiFi module used by the iPhone, and I must admit that the pattern we see supports something like that (i.e., an unfortunate combination of iPhone hardware and iOS version).

I'm stuck.

Boost

Answer 1

Mobilscan OP

Dec ’20

iOS 14.3 did not fix this.

Just created a TSI with support.

0

Answer 2

robr2112 OP

Jan ’21

Hi Mobilescan,

Do you have any updates from your TSI?

I can confirm your findings with our product line.

Problem iOS Devices include (but may not be limited to): iPhone 11, 12, SE (2020), with iOS 14 only.

NOTE:

I am unable to test iOS 14.0 or 14.1. So, I'm not sure if issue began at 14.2 or if it began earlier.
Interestingly, some of our products WORK by AdHoc even on these same failing iOS devices.

Issue seems to be a combination of: (a) HW Products with OLDER WIFI HW modules, (b) iOS devices with NEWER WIFI HW modules, and (c) iOS 14+.

0

Answer 3

Mobilscan OP

Mar ’21

Hi Robr2112,

Our supplier (of the device that the WiFi module lives in) has confirmed this to be a widespread problem.

Apple support has been fairly responsive - mainly resulting in confirmation that the basic connection attempt times out.
Still no solution, though.

We do have a few customers who for some reason has succeeded in connecting. I tend to agree with your analysis.
I hope that Apple comes up with a solution, but 14.4 didn't fix it, either.
I'd hate to have to look for a replacement WiFi module.
Considered MFi once (way back) but dropped the idea due to the amount of paper involved (and partly the fact that I strongly disapprove of the concept...).

Just waving goodbye to Apple is of course an option.

0

Answer 4

robr2112 OP

Mar ’21

Hi Mobilescan,

Thanks for the update.

FYI, I've filed a BugReport (FeedbackAssistant) about this, as well as a TSI.
Unfortunately, the BugReport hasn't gotten any traction from Apple yet, that I can tell.

A couple interesting points that I've found that allow it to work on SE/11/12:
1) Connect both iPhone 6s and iPhone SE to same AdHoc device. Communicate to it from the 6s. Now it works on the SE.
2) Using only SE, connect to AdHoc device. Then, turn AdHoc device OFF/ON. Now it works on the SE.
At least, it works until SE goes to sleep. Then, you must repeat.

So, it's clearly not incompatible. There's just something about the timing.
We believe it has something to do with ARP messages, but we're not certain.

I agree 14.4.2 has not fixed it yet.

0