Many thanks for your contribution and detailed explanation. This topic should be pinned because it will be the main issue people will have to go through when using these modules with OpenWrt (at least people that know what speed to expect).
If MCUZone is Driver Free and they use FriendlyWrt, I'm wrong to deduce that even OpenWrt could be driver free capable? I also prefer OpenWrt because, I suppose, it allows a much deeper control. However, if OpenWrt causes a reduced speed, than it's another story. We are all trying to do whatever we can to achieve maximum performance and the last thing we want to see is precious bandwidth lost, expecially when the cause is purely software.
Is there an estimate of the speed reduction when used in conjunction with OpenWrt (and related forks) ??
Yes, I really can't believe such bug is so old and still unsolved, but I don't think it is developers fault. It's probably something that should be handled from the community by submitting the needed pull requests.
@KFO May I take advantage of your deep knowledge? I'm stuck from very long time because I don't know what modem and board I should buy.
My target tower has N.5 LTE bands + N.2 NR bands (N3, N78).
MODEM:
I initially thought to Fibocomm FM350-GL. It's just $40-50 and there is a good topic here about it.
It should come with (a very old and very entry level) Mediatek T700, the same chipset that comes with Zyxel NR5103 (in my country reached a speed of around 1Gbps when placed outdoor and connected to a tower similar to mine). It has also 4x4 MiMo and an high modulation (256QAM for download and 64QAM for upload), at least this is what stated on manual (firmware 1.0.6).
However, if I have interpreted well the user manual, it only support "3LTE+2NR" or "5LTE+1NR". Whatever combo I choose I'm going to lose two LTE bands or one NR band.
Given the cheap cost of this module, I would prefer to invest more money and take something better (as long as the gains are proportional to the extra money needed).
I have checked RM520N-GL (X62) which still have an acceptable price, but seems to perform even worse: "3LTE+1NR" or "2LTE+2NR".
Even the much more expensive RG520F-EU (X65, $200 and more) still performs worse ("3LTE+2NR") except for RM521F-GL ($250 and more): "4LTE+2NR".
So, with 200$ more for RM521F-GL, I am only able to aggregate one additional LTE band for a total of 4 bands of the 5 available. This is not all proportial to the extra price.
Is an X75 able to aggregate all bands available in my tower? I don't know, but even if it could, it would be hundred dollars more respect to an already expensive X65 and just for one additional LTE band.
I think Qualcomm/Quectel are way overpriced especially because they seems to perform equally (in some cases even worse) than an old Mediatek T700.
There are several brands in the market and I was hoping to find a better module than FM350-GL at a reasonable price. What you would recommend?
BOARD:
I initially thought to an MCUZone like the one you posted. The board itself is not expensive, but once you add the needed stuff (case, heatsink, fan) it is. In addition to that, it is likely that I will end up to put the modem outdoor (on the roof) if I'll see better performance. The board with PoE support is $40 more. It is going to cost lot of money and what you get is not certainly what you paid for.
There are Raspberries, Bananas (like the one you posted at beginning) or similar, but they still become very expensive once added the needed stuff and I think mostly because such boards comes with lot of unneeded stuff, at least in my case (I will end up to connect the modem to a router, so I only need the connection from the ethernet port). I saw lot of people not recommending these popular boards anymore because now the market offer much better and cheaper alternatives, but I have yet to explore such possibility.
As of now, what to me seems to be really the best solution is a Mini ITX board. It can be found for just 20$ and some also comes with PCIe slot where, in theory, I could connect a very cheap 10Gb network card and get a future proof board that should last for many and many years. The cost of the missing parts (RAM, CPU, enclosure etc) are pretty cheap and at worse I think it will always be much cheaper than the above solutions (and I suppose an x86 is always going to be more performant). And it's still a very compact solution (Mini ITX boards are just 17cm x 17cm in size).
What you think?