$34 Smartphone Part II – Teardown

http://projectgus.com/2015/05/34-dollar-smartphone-part-ii-teardown/

by zdw • 11 years ago

98 34 11 years ago

TD-Linux• 11 years ago

Wow, I didn't expect the Red Bend hypervisor. This seems like a total disaster from a security and privacy perspective.

I really don't understand why this makes sense to do. What is so special and secret about the baseband that makes it worth the effort of running a hypervisor on such an underpowered phone?

rurounijones• 11 years ago

Well from the article it sounds like this means they don't need a separate cpu or ram to run the baseband software. less components = cheaper phone.

walterbell• 11 years ago

Israel-based Redbend claims to be the market leader (~70% share / 2B devices) in smartphone OTA updates (http://www.redbend.com/data/upl/whitepapers/from_hardware_ma...) and is expanding into automotive OTA updates, http://www.redbend.com/en/company/news-and-events/in-the-new...

digi_owl2• 11 years ago

Ugh, that marketing lingo...

hrrsn• 11 years ago

Lower manufacturing cost, I bet.

spitfire• 11 years ago

Cost and modularity.

Even the cheapest baseband chip will add a significant cost to a phone. If they can get rid of the physical baseband processor they get a major cost savings.

As for why user a hypervisor vs a user mode or kernel driver: Modularity.

Some company can specialize in producing soft-basebands (software eats the world!) and ship a simple image blob that you can drop into your virtualization host, set it to use 5% of CPU time and you're away to the races.

Might be able to bring up a baseband on a new platform inside a day.

sliverstorm• 11 years ago

This seems like a total disaster from a security and privacy perspective.

(Not that a shanzhai manufacturer making a $34 phone cares in the slightest about those things)

cnvogel• 11 years ago

Also don't expect this "hypervisor" to be a complete software package like Xen or VMware. I'm speculating here, but all that's needed is a rather fixed allocation of peripherals, interrupts and RAM for each guest (radio+SIM+a few MB RAM to baseband, everything else to Android), likely compiled statically for this particular platform. No fancy emulation of hardware or device-drivers giving paravirtualized access to complicated peripherals necessary.

In that case, and with a CPU and peripherals designed with keeping this concept in mind, the overhead will be almost non-existant compared to, for example, running the baseband functionality as a "regular kernel module"; with the added advantage of clearly separating both worlds, and isolating the realtime-requirements of the baseband from the Linux kernel.

For some similar concept, have a loot at "RTlinux", where the Linux-Kernel runs as the lowest-priority task in a very thin realtime-OS to achieve guaranteed reaction times for, e.g. motor control applications.

http://en.wikipedia.org/wiki/RTLinux

cptskippy• 11 years ago

Aren't all (or most) baseband OSes real-time OSes? You can't really run a baseband with Linux. I imagine the virtualization software is there to run the baseband OS and the Android OS side by side on the same CPU.

jjcc• 11 years ago

There are some invisible companies in China. Some are quit big. For example there's a mobile phone company called TRANSSION HOLDING in Shenzhen. In Feb it's mobile phone production is No.2 in China, next to Huawei, more than Xiaomi which is No.4. It's brand is even unknown inside China. How such a company is unknown even within China while producing so many phones? Because its market is in Africa. Its brand, Tecno, is the No.1 mobile phone in Africa

ilitirit• 11 years ago

Must be Northern Africa. I live in South Africa and have never seen or heard about that phone.

barredo• 11 years ago

I think Tecno sells mainly in Kenya and Nigeria

healer• 11 years ago

Nigerian here. Tecno is a very popular brand in Nigeria. Especially among the middle class.

userbinator2• 11 years ago

I think it's safe to say that most smartphone mainboards will look roughly the same, due to the high level of integration; although name-brand phones from Samsung and Apple tend to have higher-density layouts and actually lower integration.

Here are prices on some Spreadtrum parts:

http://www.europe-asia-electronics.com/index.php?op=stocksea....

The SR1019A is $0.564, SC2330B is $0.876, and SC6825C is $3.83. I found the VC5282 on a different site for 2.30RMB ($0.37 USD), and prices for KMN9X000RM seem to vary a lot but vary between $0.14 (possibly a scam) and $15.

It's hard to estimate the BOM cost because of all the other pieces' unknown specs, but I don't think it's more than ~$20.

When the phone is assembled you can trigger it by holding ‘Volume Down’ while the phone is off, and simultaneously plugging it into USB. I haven’t tried ‘ResearchDownload’ yet, unfortunately it sounds like it can only write images not read them – taking a backup involves flashing a working CWM for the phone model first.

That's the same method used on Mediatek smartphones; they have the bootloader in ROM too, and this is also what is used to load initial firmware on blank devices at the factory. (It's also how to recover from a "hard brick".) The ResearchDownload utility looks like a clone of Mediatek's SpFlashTool, and if the bootloader mode works in a similar fashion, dumping the full eMMC should also be possible like it is in MTK. All the bootloader does is provide commands to write data into memory and execute it.

I'd be very surprised if they were actually virtualising the baseband and applications processors on the same CPU, since the former needs hard realtime constraints. The MTK SoCs use a separate Cortex-R4 core for each modem (two in the case of dual-SIM) to do this. They could be using vLM to emulate a "virtual" SoC, allowing them to change the underlying hardware while still running the same Linux kernel. The possibility that they're virtualising Mediatek's Linux kernel on their hardware is not so far-fetched...

DiabloD3• 11 years ago

What I'm wondering is if they could be using the hypervisor to just partition the CPU, and permanently assign one of the cores to the baseband VM, and leave the rest assigned to the Android VM.

Although, the article didn't say it had an odd number of cores, so I guess not (unless it's really a tri- or penta-core SoC)

minthd2• 11 years ago

The site you mention looks veryh interesting, but they probably only give access to industry people. Is there any similar site where regular people can see reliable prices ?

userbinator2• 11 years ago

Go to "Stock Look-up" and click on "Spreadtrum".

Maybe they don't allow direct linking.

keithpeter• 11 years ago

"iFixit would approve of the H3. All you need to take it apart is a Phillips head screwdriver."

Would that imply hand-assembly in a small factory rather than large batch production?

I gather from the OA that this is basically a reference design using SoC components. Just wondering if there will ever be a Web site where I could spec a made-to-order phone in the same way that I can spec a cheap laptop? So I could have (say) a high quality sound recorder chip with 3.5mm input socket for an external microphone added to an otherwise standard phone? Or a really good camera chip?

xnzakg• 11 years ago

Project Ara!

fleitz• 11 years ago

Can you post a link to where to spec cheap laptops?

I dislike buying laptops because I can't find anywhere that does them custom for a reasonable price.

zz1• 11 years ago

Here you can spec them. Not cheap though: https://www.mysn.de

tomjacobs• 11 years ago

It's amazing that you can have a fully working internet device in your pocket now for $34. It'll be $5 in a few years. Think of the world disruption then, when all of the internet is available to everyone who can afford a $5 meal.

Let's talk about it: If you have something to say, add it here:

http://glitchclub.com/?topic=34

lovelearning• 11 years ago

"Like most phones, the H3 won’t power on without a battery connected"

Instead of a battery, I often use a constant voltage constant current 3.7V SMPS regulator board to switch on my old phones when I want to experiment with them. Connect the positive lead, ground the other two leads, and most of them (i.e., 7 out of 8) turn on just fine.

ck2• 11 years ago

This particular phone was a poor choice.

It is very outdated from both a hardware and software perspective.

You can walk into any walmart or dollar store in the united states and buy a far more modern phone for $30

I suspect there were better choices in that market they bought it.

andybak• 11 years ago

Is that actually $30 or subsidised $30?

pki• 11 years ago

subsidised $30, but you can get it unlocked anyway usually

emerod• 11 years ago

How about a prepaid Android phone for $10? So, technically it is subsidized, but there is no contract to sign.

mschuster913• 11 years ago

Hey, maybe someone of the hardware folks in here can help me out: couple friends and I want to do a student project with gsm-enabled IoT devices. Does anyone know a chipset vendor that is willing to work with students?! Chipset requirements are not huge, it should support 3G or EDGE, Wifi, CSI/DSI for screens and camera and if possible a couple of GPIOs.

We don't really want to go the route of using unlicensed phones like this one or hacks with a rpi and dozens of shields, so it'd be cool if there's anything available...

minthd2• 11 years ago

Will this do:

http://www.seeedstudio.com/wiki/LinkIt_ONE

Not on a single chip , but it uses components that are aimed at smartwatches , so optimized for size.

mschuster913• 11 years ago

Unfortunately I need Linux and a bit of processing power, and especially I need a HW design that I can modify, but thanks!

th0br0• 11 years ago

head's up: the email domain you specified in your profile is no longer registered.

mschuster913• 11 years ago

Fixed, thanks!

Already__Taken• 11 years ago

Have you seen JanOS from JSConf.eu? [Home page here](http://janos.io/)

Long story short. Mozilla are making dirt cheap phones, Buy their motherboard direct from china that goes into the phone and put a headless build of firefoxOS on it. All the hardware interfacing has been done for you.

I've no idea how this project is going. Still hard to get those phones in the UK so I've not bothered to look more than the talk and the site.

digi_owl2• 11 years ago

About storage, either look at /dev/block or install Diskinfo.

Likely the device have a number of smaller partitions (A huawei phone i have handy have no less that 19 different ones) that for various reasons are not mounted.

$34 Smartphone Part II – Teardown

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