Customers who need a replacement AirPod from Apple have in some cases received an AirPod with 2D3 firmware that is not a publicly released version of the AirPods firmware.
As described on the MacRumors forum and Reddit (via iMore ), customers who receive an AirPod with the 2D3 firmware cannot pair it with the existing, non-replaced AirPod so that the "AirPods" cannot be used together.
Apple apparently does this These “AirPods” have been shipped with the unusable firmware since March 25 or earlier, so that some customers have not had a working set of “AirPods” for a few weeks. By Reddit:
Have the same problem. Originally replaced the left one and that came with 2D3. Apple then replaced the right and that came with 1A673. I could make them mate individually, but that's ridiculous.
I finally reached a senior consultant yesterday who took a look at himself using screen sharing. He was totally confused and has done great so far. He has made himself the agent for my case and I expect a call back today after he has given me some engineering tips. These tips didn't work and now both "AirPods" seem to be fried. I can no longer pair an AirPod with my phone. The case is fine because I can pair my wife's "AirPods" with my phone via my case.
The advisor admitted that I could never pair them because the AirPod with a lower version cannot be upgraded to a non-public version. He even said that there is little documentation about it and that it is likely that 2D3 should be released but failed to come out due to errors.
Apple's support staff was unable to help customers, and even after multiple AirPods shipments, customers were unable to receive a working set. By MacRumors reader blue_marzipan:
I have the same problem and have spent the last 2 days trying to get Apple to help. The problem is that firmware 2D3 is not yet available for the update. I finally came to a senior adviser and he said he could only help me if he sent me another set, but he couldn't check the firmware before it was shipped, so it might match or not. You sent me 2 left ones, both with the 2D3 firmware, which of course is not synchronized with the other and cannot be updated. The advisor was not helpful at all. He said if a lot of people report the problem (in my case it took 48 hours to get to him), the engineers could look at it. Otherwise he couldn't do anything for me.
And by MacRumors reader SorsCode who has the same problem:
Update: Not a good one, but an update. I am now on my 4th replacement on the right Airpod and could not get one with 2D3 on it. You sent me left and right at the same time. All of my left were 2D3 and my right were everywhere. Escalate tonight to see if we can stop the madness and get a refurbished set.
According to a person on Reddit who spoke to Apple's support staff for 10 hours over the course of a week, the 2D3 AirPod problem appears to be somewhat widespread, and since Apple's teams are currently working from home, there are there is no word about when the new 2D3 firmware could be released to solve the problem.
There will be no solution until the new firmware is released, but in some cases, the Apple Support team has replaced the affected "AirPods" with new feature sets that run older firmware. However, this doesn't appear to be universal, and there are still some who have difficulty solving the problem.
This appears to be a problem primarily affecting customers who own the second generation “AirPods”, but there have been some reports from customers who have AirPods Pro that have been affected.