It’s well-known that buying Flash storage devices from cheap online retailers is fraught with danger. Stories abound of multi-gigabyte drives that turn out to be multi-megabyte ones engineered to falsely report their capacity. So when [Jason Gin] found a source of 64GB Toshiba eMMC chips for only $6 per device he bought a few, but was prepared for disappointment.
To test them, he decided to use an SD card interface. There are minor differences between eMMC and SD, but the interfaces are electrically the same and in most cases an SD controller will happily do business with an eMMC. It was not however an easy task to connect the two — these eMMCs were in BGA packages, hardly the easiest ones to work with. He resorted to dead-bug soldering the relevant interface wires to SD lines, and connecting up his computer.
His first attempt was something of a failure, wiring the chip to the PCB of a cheap USB-to-SD adaptor. This did not put him off though, he followed it up by cracking open a very old 2GB SD card that contained a PCB instead of being potted, and soldering his eMMC in place of its Flash and controller. This even fit in the original SD housing, and met with success when plugged into more reliable SD card readers. He was thus able to confirm the capacity of his chips.
His blog post is worth a read for more than just the very fine soldering involved. He takes us through some of the intricacies of SD interfacing, as well as talking at length about the decoupling and termination required to make a reliable connection. We particularly like his use of an area of unconnected BGA balls as prototyping space for decouplers.
If you marvel at the exceptional dexterity required for hand BGA work, we’ve a couple of other treats for you. There is this TI infra-red sensor BGA soldered to a piece of stripboard, and this wafer-level chip package soldered to an SOIC prototyping board.
An SD card is surely not an enterprise grade storage solution, but single board computers also aren’t just toys anymore. You find them in applications far beyond the educational purpose they have emerged from, and the line between non-critical and critical applications keeps getting blurred.
Laundry notification hacks and arcade machines fail without causing harm. But how about electronic access control, or an automatic pet feeder? Would you rely on the data integrity of a plain micro SD card stuffed into a single board computer to keep your pet fed when you’re on vacation and you back in afterward? After all, SD card corruption is a well-discussed topic in the Raspberry Pi community. What can we do to keep our favorite single board computers from failing at random, and is there a better solution to the problem of storage than a stack of SD cards?
Continue reading “Single Board Revolution: Preventing Flash Memory Corruption”
Sometimes we feel confident in our soldering skills (but only sometimes) — and then we see something like this done.
Someone over on the XDA developers forum managed to upgrade his Nexus 5 from 16gb to 64gb — and not only that, upgraded the eMMC type from 4.5 to 5.0 so it writes and reads much faster.
While the details on the actual conversion are a bit vague, we did manage to dig up another video of someone replacing an eMMC chip from a Samsung Note 2.
It most certainly is possible… but would you look at the size of that chip!
Continue reading “Upgrading a Nexus 5 eMMC to 64GB”
This morning I went to a fantastic talk called Hack All the Things. It was presented by GTVHacker. If you don’t recognize the name, this is the group that hacked the GoogleTV. They haven’t stopped hacking since that success, and this talk is all about 20+ devices that they’ve recently pwned and are making the info public (that link still had oath when I checked but should soon be public).
The attacks they presented come in three flavors: UART, eMMC, and command injection bugs. I’m going to add the break now, but I’ll give a rundown of most of the device exploits they showed off. I found all amusing, and often comical.
Continue reading “DEFCON 22: Hack All the Things”