By chance I discovered that TP-link UB400 works the same as Yealink's own adapter. The phone thinks it's a Yealink adapter - the same chipset I think. Difference is that it's only $10 each and TP-link is easy to find.
What's funny about this is it reminds me of that stupid thing from last year '"could our ancestors see blue?" that people kept sharing on Facebook because of that blue/black/white dress thing which made no sense at all. It's claimed that nobody until very recently used the term blue to describe the sky, or ocean, etc.
While it's true that the Greeks didn't really do this, that isn't true for everyone else. Naturally the original scholar who thought up this weird idea about 160 years ago basically thought Greeks were the only source material of any work worth looking at, and since they didn't use colour descriptions as English speakers did, therefore every other language must be the same*.
Anyway, speakers of Germanic languages like the Anglo-Saxons, Vikings, and so forth did use blue and did describe the sky and ocean as blue, in fact one of the very oldest rune writings in existence describes the "blue horizon", and "blue waves" of the ocean. It even uses "into the blue" "út ínn blá" (I think) in idiomatic phrase. The point is, yes, people used word used the word blue, hence our friend Harald here.
This post isn't really that important, but I figured language dorks might enjoy it and since nobody else was talking I figured I'd bring it up being that it involves language and Old Norse.
*This also reminds me of the popular belief in Turkey that Turkish is the root of all languages.
Source: myself, I am a huge dork and at university I was only one of four people in an Advanced Anglo-Saxon English course. Old Norse and Old English were almost mutually intelligible, so I can read a lot of old texts, or at least get the gist.
And to derail even more:
I am not a native English speaker, but I know it better than most natives do, and even so I'm not the kind to correct people's grammar or call myself a grammar nazi. For me, English's spelling being so broken means that it's all a joke to begin with, so as long as the message gets across clearly, it doesn't matter.
Native English speakers tend to not understand how broken their writing system is and that it's a complete joke to take pride in it. Nobody takes pride in a toilet that takes 400 steps to flush it instead of 1. Hell, many have told me "English is the hardest language to learn," but that's only because of writing, it's actually pretty easy. Then again, I don't expect much from people who often think English comes from Latin and isn't a Germanic language. There aren't really important things to know anyway, except how broken the spelling is, people should know that most children in non-English or French speaking nations learn to read/write nearly every word in the first year or two of school, where as even by grade 8, most English speakers can only read/write 40% of the most common words, and rarely improve into adulthood. Waste of tax money, time, effort, but... whatever.
Once you do that, you'll want to rebuild the bluetooth stack. Remove the device from your phone, power off, power back on, re-pair the bluetooth. That will rebuild the bluetooth stack and is best practice after updating firmware. (I spend A LOT of time on PLT's forums).
Also, I don't recommend the M series. They are the stupid cousin of the Voyager series.
Sadly my BT isn't any of those. It's the M55 - Just a simple unit.