New FP2 Motherboard

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it’ interesting but it means one more IC that can’t just be disabled by a simple EN signal and therefor one IC that consumes Power even if there is no load on the device, but it remains interesting


What a seriously high attitude project! I have done MCU and power boards for industrial control, but am now into other things.

Idea to ease software development:

In the previous millenium, i had a PC with two IDE drives, and a switch that swapped which was C: and D: by manipulating the select wires before (re)boot. Good for dual booting / development / crashtesting… and from the booted system you could install/repair/restore/backup the other.

Maybe something like that could be possible by some miniature switch(es) and simple logic, manipulating memory enable/adresses and preferrable also physical write protect.

As switches take up space, maybe implement only a possible addon by cutting some link and solder in wires.

Having said that i have no idea about how Andriod boots… But as an example i currently would like to run the stock OS while being able to dual boot to Sailfish, and have a common store (i.e SD card)


Oh you said it - FPGA. I like those types even more since I know about this product.
That guy seems to love using them and has quite a bunch of very nice products on sale.
And the good thing is - he usually keeps a useful surprise gimmick for the customers, just something other companies would not even think of implementing.

Wouldn’t it be nice to have a unique gimmick in our FP3 (as well) which attracts some users just because of this? We had modularity, an expansion port and an open bootloader which surely caught some users just for tinkering.
How about dual boot possibilities?


Aha - yes, I am in for that, sure!!

How about reality in this point Leo??

You are running at high pace man…

NFC - and QI is both possible at once? Maybe there is a chance for an answer. please


Actually now they have so called bootloaders that act as the switch: the program decides which ROM to branch to and there used to be some custom bootloaders that allowed to choose between two ROMs for dual booting different flavours of Android (or Android/Sailfish probably as well).

I know Zynq has the possibility to boot from Internal Flash or SD card so there you have your failsafe multi-boot :wink: (but it doesn’t embed the hardware Intel SoC has…).


Yes, the great thing about FPGA is that you can emulate pretty much any piece of hardware (GPU, sound, network, …) as long as you have it connected to output devices (screen, speaker, RJ45 PHY/USB/WiFi chip).

But SoC are easier to work with, as @Leo_TheCrafter wisely said so for this first version it’s just great.

As for dual boot, it’s “just” in the bootloader so it’s not too much a specific hardware setup.


Well, there was EFIDroid multiboot, but the last thing I heard is that it doesn’t work with latest OS versions on the FP2 anymore.


I don’t know if NFC and QI are possible at the same time, but they don’t have to. NFC is only enabled if it’s really needed


I have the rather diappointing news that the LTE module will probably be soldered to the MB and won’t have a socket anymore. The reason is space. Not only does a socket take up more space in the x and y axis it is also significantsly higher than a regular BGA.
This all might sound reallly disappointing but it’s not that bad. BGA isn’t to hard to solder you just need 5 things to do so

  1. Hot air Rework station ( I have one for 38€ and it works just fine)
    2.Soldering Iron ( any cheap soldering iron will work)
    3.Solder wick
  2. The component you want to replace

This isn’t to complicated if you have the equipement. And if you don’t have a hot air rework station I strongly recoment buying one, because as i said even cheap ones for 38€ will work most of the time. If you have a hot air station you could also replace the eMMC and the RAM or even the CPU if you want to. I will release documentation how to solder the compenents. And even if you still don’t want to solder it on your own you can still let it be done professionally and mybe it’s possible to send the module to FP and let them replace it.
a soldered module might even have better signal characteristic than a socketed one and the overall size of the package decreases dramaticly. Sorry but I had to do it because I completely underestimated and miscalculated the size of the socket but now that the module is soldered I have even more space for creative extensions and functions


If possible, could you use a pad size for the BGA to extend outwards a
hair more than the standard BGA module to allow for easier soldering?



The module isn’t BGA, bute more of a soldered LGA. It should be easy to solder because even the smalest pads are 1mmx0.5mm so they aren’t nearly as small as the CPU with it’s tiny 0.25 mm solder balls


Wow, ambitious project!

I definitely don’t have the plan to run Windows 10 on a phone, but Linux could be interesting.

Maybe a https://postmarketos.org/ port could be an option?


me too, fast 4G isn’t that important but 5G would be interesting as I don’t watch videos or use other high bandwidth demanding services when I’m on the go.
The other things are important, 2 SIMs, SD, NFC etc.
@Leo_TheCrafter if you really gonna make this happen that will be a huge step forward in anything what Fairphoners believe in.
I wish you the very best and huge support from the community.

When you got a moment would you mind to share your learning and engineering, as that could kick off even other projects.
You gonna be the next fairphone hero!



Thanks that you respect my work. I don’t have that much time, but for i little post in the Fairphone Forum is always enough time. If you have some questions about the board or about hardware development in general you can always ask me that question.
By the way: I have a lot of little gaps onthe board that are too small to fit large ICs, but meight be big enough to fit small ICs. Maybe Sub 1 Ghz ?.
I you have some creative ideas what to do with them beside from Capacitors that would be very interesting


Maybe you can copy the original expansion port. This would ensure compatability to these projects:

I post this also as inspiration for other ideas.


this would be a great idea, if a have enough usb ports left i can di this too



Yep, the bootloader.
What makes me wonder is why some bootloaders fail on FP2 these days like EFIDroid. I know from desktop Linux there is Lilo or Grub (2) most common. If things fail there is still the option to manually enter boot options in a command line to make things work anyway. But as it seems there is no fallback for Android (embedded) bootloaders.
EFIDroid does not have this option so actually it’s not usable on FP2 with the latest OS version(s). At least that’s how I think the situation is.

Here it needs a good hardware engineer for embedded systems. FPGA would require a good software engineer too.
So at last it would require even more engineering to get the system running, but flexibility would be a lot higher. Nevertheless it’s a nice idea.


So that’s your requirement. I do believe these days the higher demand is on 4G as this is more spread and whenever 5G actually will be usable for end users we will have to accept what’s there but also keep options available (not having to buy another device) to hook up to 5G once it’s finally here.
I think all this rising cloud computing and online data sharing will require more bandwidth. I think the demand on video streaming, music streaming like spotify, netflix etc. is already going on quite a lot. And actually we are still having 1k display resolution. 2k and even 4k is our there already and some handsets can deal with them. Also it’s not necessarily a user wanting to have the highest available video quality on his way but the pure user mass using any kind of streaming service which is still growing will have the need of a fast mobile data service.


I agree that we wil need fast LTE but 10 mbts are still enough, I mean you can stream FullHD videos with that bandwith, which is quite nice. Also many users stream when they are home and I have integrated a very powerful WiFi chipset from TI


I forgot to mention, this guy who keeps several web sites btw. is a hardware engineer running his computer hardware development business since the 90s.
I had a few talks to him and think besides being a very experienced developer he is also quite friendly and communicative.

His friendliness in the past sometimes got him into trouble and disappointment when collaborating with other enthusiasts wanting to realize an own (hardware) project.
So he may not be that open anymore if there is someone looking out for an option to get their PCB layout finalized or equipped and soldered for prototyping or mass/batch production.

So if FP is not fully into collaborating with your project maybe he is willing to provide some advise or help.
Usually he keeps to state-of-the-art regulations and development/production standards and afaik also is certified.
Take a look at some of his prods, he’s running a store meanwhile.


Thanks for this very valuable information. I will contact him later when I have some more documantations about my project


I would guess part of the problem lies in the absence of BIOS on phones. On desktops, the BIOS/UEFI serves as a kind of I/O “unifier” that makes things much easier to initialize (RAM, video, keyboard/mouse, …). I don’t know enough about the electronic boot process on phones, but from my (limited) experience, the ARM runs a vector from its flash which is the “bootloader”, taking over to load appropriate OS images (like Recovery or System) from eMMC, Flash, or whatever device it was designed to use.

Each phone having different components addressed in different ways not “unified” by BIOS (not even talking about the ARM processor itself which doesn’t necessarily use the same instruction sets across different revisions), a bootlader has to be customized for a specific hardware layout (in my understanding), making it really difficult to make it generic for any phone.

I think people like @z3ntu or @chrmhoffmann have a very deep knowledge on that subject and can probably correct my mistakes. :slight_smile: