A couple weeks ago my speaker stopped working. No dinging for texts, no speakerphone, no media volume. Tried soft restart and didn't work. I then got myself onto the 10.2.1.1259. Everything worked great, including speaker (and FM radio)! I installed a few apps, including sideloading and apps directly from Snap. I was careful to test my speakers between apps installs lest the problem came back. Lo and behold the speaker died on me again later that day/the next day. I did a security wipe with the 10.2.1.1259; the speakers came back again.
Now I am 99% sure it's a SW problem, 1% chance it's a loose connection or something. A couple days later, the speakers died again. This time, as a hail Mary, I fell back on something I learned since I got my first BlackBerry 3 yrs ago, but which I had banished from my mind: the battery pull.
It may have, not too sure. I had a leaked version of OS 10.2.0.xxxx installed when the problem first started. I didn't have any Android apps on there at that time. Just things like FB, Twitter, Flixster, a flashlight app, Nobex radio, and an LED app. Had at least 5GB of space on the phone left too. I had had the phone for almost 4 months (most of the time was on the leaked OS) before the issue surfaced.