Denver IR-135B internet radio, unboxing and review

The Denver IR-135S is the same thing. It is available in two versions, with a black front (as is mine) or a silver front. The B/S suffix just means Black/Silver.
Internally, it is based upon an ESP32.
I've been listening to mine for a few hours now using headphones. It sounds quite good, and hasn't glitched or messed up, even while I was uploading this. The battery has used about half of its charge in around two and a half hours (but don't quote me on this, I wasn't really paying attention).
It's quite interesting to me that it would cost about the same to buy all the bits to make one, so might as well get a premade unit that works well and, actually, looks pretty good.
Looking in the user guide, I suspect the problem with the number keys is that they actually work by being associated with the first three positions in the favourites list, and holding down the button (to assign a station to that button) works by shifting the list around to move the station to that position, and it's this that's getting screwed up if I try to assign favourite #2 to button/position #1. It's not entirely clear how it works, but it's still a bug as it shouldn't be corrupting the favourites list (either by working properly, or - if I'm simply doing it wrongly - by not allowing that action to happen).
Not mentioned in the review (as I hadn't found it yet!) is that there is an equaliser with ten predefined options (including heavy metal 🤘), and if those aren't sufficient, you can define a custom EQ setting with five bands, plus a 3D separation control for enhancing stereo.
The audio track heard at the end is Embers Circling Downwards by Sarin.
It has been released under an Attribution licence (creativecommons.org/licenses/...) and you can get a copy from freemusicarchive.org/music/Sa...

[@david_pilling]

Looks good - potential for someone (and I could not find it) to do their own code for it.

[@heyrickblog]

Yes, it's possible. A little later I hooked up the internal serial port (it's on my blog) and it responds to the ESP32 flashing software. I took a copy of the firmware, and yes, it would be possible to create and upload a replacement.
Though, to be honest, apart from a few bugs (mostly in manipulating the station list), I haven't had problems with the radio or been frustrated by it's behaviour. I use it often, like all day most weekends and many evenings (having discovered Epic Rock Radio 🤟), and I'm pleased/astonished/mind blown to say that it functions, it behaves, and it doesn't have a UI that totally sucks. It's actually useful!