Discussion about Dogwood batch


#1

I’m glad to see the update on the Dogwood batch.

I loved seeing the photos of new PCB, but they are too blurry for me to see the markings on the chips. From what I can identify, it doesn’t look like any of the big chips have changed in Dogwood.

Besides this with Chestnut we discovered that ST Micro, the manufacturer of the TESEO LIV3 GNSS multi constellation receiver we are using in the L5, silently changed the recommendations for the antenna input electronics design. Now in Dogwood we see that GNSS reception still wasn’t great so we went back to suppliers and the drawing board, applied some more changes and are now finally getting a fix!

Does this mean that the Librem 5 will use a different GNSS, or that Purism is keeping the TESEO LIV3, but changing the antenna and some other electrical components associated with the GNSS?

Can anyone identify what is the purpose of the red, black and yellow wires next to the ribbon cable and the black wire in the upper corner?

Is it easy to detach the ribbon cable that connects the daughter PCB with the USB-C connector? If it is easy to detach, then it will be much easier to replace if the USB-C connector gets broken.


#2

just read the blog article.

Dogwood represented a much larger change–a CPU flip to the other side of the PCB to help with heat dissipation–that meant a full redesign of the PCB layout.

indeed ! that almost seems like designing a v1.5 L5 in just a short amount of time … no wonder you’re so late !

hopefully this only happens ONCE as a learning experience so we can expect a v2 to arrive on time if we’re all still here this time next year !


#3

I’ll hazard a ques that those would be for power. For continuous testing battery changes are inconvenient (when not testing anything related to those).

It’s probably just some trick of the light and a bad photo, but at first I thought there was heat damage and some dents on that board and thought, “Nice - test to fail. I wonder if they got flames from it…?” But it’s probably not. Then again, I hope idiot and fault testing are made (“Hmmm… someone might try to charge it straight from the mains - let’s see what happens…” vs. “What if the battery goes bad bad.” :wink: ). Based on the text, it’s probably less exciting things done.

@amosbatto Isn’t the SIM slot in a new way too (comparing to images seen last fall) - access from the battery compartment and not from the side, if I’m reading that image right?


#4

a black PCB would be nice for Evergreen … green reminds me of my old nVidia Quadro (RIP)


#5

My understanding from what they wrote there is that they are still using the same GNSS receiver, but making some kind of changes in how it is used, maybe the placement of it in relation to other parts, and something with the antenna. That they are “finally getting a fix” means, I guess, that they have decided on changes they want to make and have ordered that (or changed previous orders) from some supplier(s) who will hopefully then deliver something that can give better GPS/GNSS reception. But they have apparently not received the fix yet (then they would write “have gotten a fix” rather than “are getting a fix”) so it remains to be seen if the reception will improve after the changes.

Edit: as @ThisGuy says below, “getting a fix” could instead mean they are getting a satellite fix.


#6

I honestly thought the same. But it might just be something from the manufacturing process.

This post from Purism is a very welcome read. This is not easy work, and I applaud them for the hard work they are accomplishing here. This will hopefully pay dividends in the future with other projects.


#7

Hopefully. And highly probably to my mind. The kernel things go upstream, driver and firmware gets upstreamed. Apps with libhandy could be used on all linux based mobile devices. And maybe the Purism hardware could lead to some kind of i.MX smartphone reference design oder something like that?


#8

I read that excerpt as they are now getting a satellite fix; that after their adjustments they are now able to acquire the GNSS GPS signal in a usable state. Not necessarily that it’s a solution or discovery “fix” they have yet to implement in hardware and/or software. But your guess is as good as mine I suppose.


#9

Ah! Yes, that makes sense. Probably that’s what it means. :smiley:


#10

Dogwood has added a new internal piece to cover the cellular modem and WiFi/Bluetooth. Since there is already a back cover, I wonder why this extra piece is necessary.

At first I thought that maybe the cellular modem was emitting too much RF radiation, but it looks like that internal cover is all plastic, so it isn’t going to block much radiation. My second thought was that maybe the M.2 cards were coming loose and it is designed to hold them in place, but the back cover could easily be designed to hold the cards in place. My third thought is that internal cover is designed so that it is necessary to loosen screws to get to the phone’s hardware, so you can paint lipstick over the screws to tell if anyone has loosened the screws to access the cellular modem and WiFi/Bluetooth.

That last theory makes the most sense to me, but then I notice that a white plastic cover has also been added over the USB daughter card below the battery, and that part is already covered by the internal plastic cover, so why add another piece? Was that bottom white cover added to give the phone more strength or does it stop the USB port from wiggling so it doesn’t break its solder joins?

I wonder if there is any way that you would know whether someone has modified the OpenPGP smartcard, SIM and MicroSD card, because you can access all of those components without taking out any screws. Will the Librem Key have some way to detect that those components have changed?

I’m glad that Dogwood is getting better cooling. I’m just sad that I won’t be able to take apart the entire phone without putting on new thermal paste. The curious cat in me will want to see the back of the PCB, since that is were all the interesting chips are. I’m guessing that just putting a graphite sheet over the SoC on the PCB wasn’t enough to dissipate the heat.


#11

Maybe it is to hold the cards in place while you are replacing the battery. :neutral_face:

When you say modified, do you mean “in transit” (anti-interdiction) or long after receipt of your device if you temporarily “lose custody” of your phone?

I would suppose that the smart card is naturally tamper-resistant.

As the phone can’t boot from µSD card (my assumption), the operating system itself can manage the integrity of the µSD card - within reason and if that is important enough to you. In other words, chain of trust is that the (hypothetical) Librem Key ensures that the eMMC drive has not been tampered with and then if the operating system, booted off the eMMC drive, chooses to then it can ensure that the µSD card has not been tampered with.

To be honest, all I myself am likely to put on a µSD card is an (encrypted) synch of my music and photo collection - and if nasty government agents tamper with that, it should not compromise the integrity of the device. (If crossing a border, as previously stated, I would leave the µSD card at home. One less thing to worry about.)


#12

I would think it’s to keep dust/etc out when replacing the battery since most of the time you’re likely to swap the battery you aren’t likely to swap anything else.


#13

When you first receive the device from Purism, I assume that it will come without a SIM, microSD card or OpenPGP card. I was thinking about the situation where you lose custody of the phone.

I guess that there will be an option to encrypt the data on the microSD card just like you can encrypt the internal Flash memory drive, so it would be hard for someone to unencrypt it, change data and then reencrypt it without access to your encryption keys and your password to unlock the phone.

However, if someone takes out your OpenPGP card, then you are screwed if it holds the keys to unencrypt the data on the internal Flash memory and on the microSD card. You have to have a backup copy of your OpenPGP card or you can never access your own data.

I’m awfully glad that I’m not a spy, because just thinking about these problems gives me a headache.


#14

Maybe it is just a dust cover, but it seems to me that they should have used one plastic panel that covers everything if the goal is to protect from dust, since it wouldn’t have any seams. I wonder why they decided to add a separate panel covering just the M.2 slots.

The USB daughter card already has a black plastic cover, so why add a second white plastic cover?

I am struck by how thick the phone is. The average phone today is 8 mm thick, whereas the Librem 5 is almost twice as thick at 15.5 mm thick. It will never slip out of your hand because it is too thin and I doubt that it will bend in your back pocket like the iPhone 6, but it certainly won’t win any style awards. Being thick gives more room for the hardware kill switches on the side of the case and for M.2 cards so the cellular baseband and WiFi/BT are replaceable.

I wonder if being 7.5 mm thicker and 50 grams heavier than the average phone will stop some people from buying the Librem 5. I know that some of my female friends complain about how modern smartphones have become so large that they don’t fit in the pockets of their jeans.


#15

i don’t recommend anybody to carry ANY phone inside the jeans or in close proximity to the body/genitals.

if the librem 5 has all kill-switches flipped OFF so no send/receive occurs and the pockets are MILSPEC ones (i.e they can hold a standard AR assault-rifle MAG) then i’d be willing to compromise :slight_smile:

i’m not a spy either but i do like me some MILSPEC gear to complement this sweet piece of tech …


#16

There is the small matter of someone wanting to call you - so cellular modem killed more or less implies that the phone is outbound calls only. Or you’ve gone undercover - maintain radio silence - and the phone is no calls at all. :slight_smile:


#17

yeah that tends to happen when you go to sleep :rofl:


#18

Now I feel compelled to let the world know that “Miss Congeniality” was released as “Miss Undercover” in Germany. /off-topic


#19

Just saw the recent Purism video and I have to say that the team is doing a great job on the phone!


#20

i know Purism gets a kick back of snooptube but it’s probably only something marginal at best

here is the latest post about dogwood in glorious visible text for your convenience > https://www.youtube.com/watch?v=2HIcwP6zVEQ

lbry > https://lbry.tv/@lbry:3f/2020-0518devnews:a < try the native android beta app
lbry > https://lbry.tv/@lbry:3f/paid-content-beta:b < why not go for it ?