How to RE-fix my volume level?

[Android Central Question]

I don't know much of anything about Android systems, so I'm hoping someone can help me here. I use a Fiio M7 as my main music player, and primarily I use my AirPods with it. When I first paired them, I noticed the volume level was very low, even at the maximum setting. After some googling, I enabled developer options, and set the Disable Absolute Volume setting to ON. That fixed the problem, and it's been fine until about a week ago, when it suddenly reverted back to the quieter volume levels. It might worth mentioning that I regularly switch the AirPods between my iPhone and the FiiO, but again, until now this has gone without issue.

I've now unpaired, forgotten, re-paired, restarted the device, switched that setting off and on several times (and all of these in every possible order), and done a complete factory reset, and the low volume persists. I'm wondering what else I could try to get this fixed.

I've read that the Android OS this device runs on is a very pared down version: it says

Kernel version 3.18.14-user-g3a4465b-dirty
FiiO@asc #112
Build number 1.0.2

Is there something I'm missing here?Is there a VERY specific order I need to be following these steps in that I'm somehow failing?

 

[VidJunky]

Being a lay-person on this topic it seems that everything worked, kind of regardless of the order you performed them in initially, so the fact that it is not working now would suggest that something else has changed. Since Android and Apple versions update from time to time, my first feeling is that something updated and this update overrode whatever changes you made. I could very easily see Apple saying that they will allow use with Android but let's make it undesirable… My very first thought however was that you damaged the unit by exceeding the limit, often these limits are not just put in place to protect the user but also the device. However you did not mention if the volume levels remain low when using the iPhone, which would be a key to understanding if damage was done. I suppose you could register an account to reply back to this thread.