Digging Deep Into SD Card Secrets

To some, an SD card is simply an SD card, notable only for the amount of storage it provides as printed on the label. However, just like poets, SD cards contain multitudes. [Jason Gin] was interested as to what made SanDisk’s High Endurance line of microSDXC cards tick, so he set out to investigate.

Naturally, customer service was of no help. Instead, [Jason] started by scraping away the epoxy covering which hides the card’s test points. Some delicate soldering was required to hook up the test points to a breakout board, while also connecting the SD interface to a computer to do its thing. A DS Logic Plus signal analyzer was used to pick apart the signals going to the chip to figure out what was going on inside.

After probing around, [Jason] was able to pull out the NAND Flash ID, which, when compared to a Toshiba datasheet, indicates the card uses BiCS3 3D TLC NAND Flash. 3D NAND Flash has several benefits over traditional planar Flash technology, and SanDisk might have saved [Jason] a lot of time investigating if they’d simply placed this in their promotional material.

We’ve seen other similar hacks before, like this data recovery performed via test points. If you’ve been working away on SD cards in your own workshop, be sure to let us know!

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Hackaday Links: July 19, 2020

Care to flex your ethical hacker muscles? The Defense Advanced Research Projects Agency, better known as DARPA, is running its first-ever bug-bounty program. The event is called “Finding Exploits to Thwart Tampering”, or FETT — get it? Bounty hunter? Fett? — and is designed to stress-test security hardware developed through DARPA’s System Security Integration Through Hardware and Firmware, or SSITH. Tortured backronyms and pop culture references aside, FETT will start this month and go through September. This is not an open challenge per se; rather, the Red Team will be coordinated by crowdsourced security research company Synack, who has called for security researchers to sign on.

The Linux kernel development team has decided to join the trend away from insensitive terminology like “master/slave” and “blacklist/whitelist” in coding style. A July 4 proposal by kernel maintainer Dan Williams goes into some detail on the logic of making the change, and it’s quite convincing stuff. It’s hard to argue with the fact that code reviewers can easily be distracted by coding style changes, so replacing terms that have become lightning rods only makes sense. Linus himself has signed off on the changes for all future code; the current terminology will only be allowed for purposes of maintaining older code.

Some stories just leap off the screen when you’re scanning headlines, and a story with the term “narco-antennas” practically begs further investigation. It turns out that the drug cartels in Mexico (and probably elsewhere, but the story focused on Mexico) are quite sophisticated in terms of communications technology. Eschewing cell phones for some of their communication needs for obvious reasons, they still apparently leverage the cell system by installing their own transceivers at cell sites. This can lead to some tense moments for the engineers who maintain legitimate gear at these sites; the story above recounts one hapless tech who powered down a site to make some repairs only to be confronted by armed men upset about the loss of their radios. It’s a fascinating look at the underworld and their technology, and we can’t help but feel for the men and women who have to face down these criminals just to do their jobs.

Way back in January — remember January? — we kicked off the 2020 Hack Chat series with a fellow named Alberto Caballero, principal investigator of the Habitable Exoplanet Hunting Project. At the time, I was blown away by the fact that the tiny changes in intensity caused by planets transiting across their star’s face were detectable on Earth with instruments an amateur astronomer could easily afford. And now, the project’s crowdsourced planet hunters have hit pay dirt, with the discovery of a Saturn-sized exoplanet in orbit within the habitable zone around star GJ 3470, also known as Gliese 3470, a red dwarf about 30 parsecs away in the constellation Cancer. Their paper is still in preprint and hasn’t been peer-reviewed yet, but it’s exciting to see this kind of citizen science being done, and we’d like to congratulate the team on their achievement and wish them continued luck in their search for “Earth 2.0”

And finally, if you can’t stand the idea that future archaeologists may someday pore over your code in an attempt to understand the digital lives of their long-dead forebears, then you might want to skip this story about how GitHub shipped 21 terabytes of open-source code to cold storage. The destination for the data, contained on reels of archive film and shipped on two pallets, is the world’s long-term memory: the Artic World Archive on the island of Svalbard. Perhaps better known for the Svalbard Seed Vault, where the genetic diversity of the world’s plants is stored, the Artic Code Vault is in a nearby abandoned coal mine and set deep within the permafrost. The rationale for making the effort to preserve code makes for some interesting reading, but we can’t help but feel that like the graffitists of Pompeii, if we’d known someone would be reading this stuff in a thousand years, we might have edited out a few things.

Upgrading The RAM In A 25 Year Old Oscilloscope

From reading his extensive write-ups on the subject, there’s one thing we know for sure: [Tom Verbeure] loves his Tektronix TDS 420A oscilloscope. While it might be older than some of the people reading this, it’s still an impressive piece of hardware with more than enough bells and whistles to keep the average hacker occupied. Especially if you’re willing to perform some hardware modifications.

Note the battery to retain calibration data.

[Tom] already knew how to tickle the scope into unlocking software features, a process not unlike what we’ve seen done on more modern scopes. But there’s only so far you can get by toggling software flags.

Some of the more advanced features that are turned off in the firmware actually need additional hardware to function. Simply bumping the sample points to 120,000 in software wasn’t enough, the scope actually needs the memory to hold them in.

Now logically, if there’s a software option to increase the number of samples, there must be a hardware upgrade that goes along with it. Sure enough, [Tom] found there were 6 open spots next to the scope’s existing M5M51008 static RAM ICs.

As luck would have it the chips are still available, albeit from a different manufacturer and a bit faster than the original parts. Digikey wouldn’t sell fewer than 100 of them, but UTSource was happy to sell him 10. In this case, the parts were cheaper than the shipping cost. Installation was about as straightforward as it gets, though [Tom] does note that he had to keep the board powered up during the operation or else the scope would have lost its calibration data.

Squeezing more features out of modern scopes like the Rigol DS2072A just takes a USB cable and some software. Sometimes it’s only a matter of tapping in a code. But we certainly appreciate [Tom] putting in a little extra effort to get the most out of this classic piece of hardware.

This 68k Board Is About As Simple As It Gets

For those of us who remember the Motorola 68000 microprocessor, it’s likely that a sizeable quantity of those memories will come in the form of a cream or grey box with a Commodore, Atari, or Apple logo on it These machines were the affordable creative workstations of their day, and under the hood were a tour de force of custom silicon and clever hardware design. We might, therefore, be excused for an association between 68000 based computers and complexity, but in reality, they are as straightforward to interface as the rest of the crop of late-1970s silicon. We can see it in [Matt Sarnoff]’s 68k-nano, about as simple a 68000-based single-board computer as it’s possible to get.

But for all its simplicity, this board is no slouch. It packs a megabyte of RAM, 64k of ROM, a 16550 UART, and an IDE interface for a CompactFlash card. There is also provision for a real-time clock module, through an interesting bit-banged SPI interface from the 16550’s control lines. There appears also to be a 50-pin expansion header.

Software-wise there is a ROM monitor that provides test and housekeeping functions, and which loads an executable from the card plugged into the IDE interface if there is one. This feature makes the board especially interesting, as it opens up the possibility of running a μClinux or similar kernel for a more fully-featured operating system.

The 68k doesn’t receive the attention here that some of its 8-bit contemporaries do, but it still appears from time to time. We’ve certainly featured at least one other 68000-based SBC in the past.

Thanks [Anton] for the tip.

RC Car Becomes Cable Cam

The prevalence of drones has made airborne photography much more widespread, especially among hobby photographers and videographers. However, drone photos aren’t without their problems. You have to deal with making the drone follow the shot which can be difficult unless you have a very expensive one. Worse, you can’t really fly a drone through heavily wooded or otherwise obstructed terrain.

[Makesome’s] friend faced these issues and wanted to buy a cable cam — a mount for the camera that could go back and forth on a cable strung between two trees or other structures. Instead of a design from scratch, they decided to cannibalize a cheap RC car along with an HP printer and the effect — as you can see in the video below — is pretty good.

Repurposing toys is an honored tradition and, after all, what do you need but a motor that goes forward and reverses? We can’t help but notice though that toy hacking is much easier now that you can 3D print custom widgets to connect everything together.

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The Real Story: How Samsung Blu Ray Players Were Bricked

In June, many owners of Samsung Blu Ray players found that their devices were no longer usable. Stuck in a boot loop, speculation was rife as to the cause of the issue. Now it seems that the issue has become clear – a badly formatted XML file may be responsible for the problems (via The Register).

The problem stems from the logging system that stores user data and passes it back to Samsung over the Internet. Which data is logged and sent back is managed by an XML file which contains the policy settings that control this behaviour. According to a source known only as “Gary” “Gray”, the XML file posted on Samsung’s servers on June 18 featured a malformed list element. This caused a crash in the player’s main software routine, leading the player to reboot.

The failure was exacerbated by the fact that the XML file is parsed very early in the boot sequence, even before checking for firmware updates or a new XML file. This has prevented Samsung from rolling out an update or fix over the air, and is why the player gets stuck in a loop of continuous reboots.

Reportedly, the file can be found at this URL, though is now an updated version that shouldn’t brick players. Samsung have had to resort to a mail-in repair scheme, wherein technicians with service tools can manually remove the offending XML file from the player’s storage, allowing it to boot cleanly once again. While this shows our initial assumptions were off the mark, we’re glad to see a solution to the problem, albeit one that requires a lot of messing around.

[Thanks to broeckelmaier for the tip!]

A Tin Can Modem, Just For Fun

Anyone old enough to fondly recall the “bleep-burp-rattle” sequence of sounds of a modem negotiating a connection over a phone line probably also remembers the simple “tin-can telephone” experiment, where a taut string transmits sound vibrations from the bottom of one tin can to another.  This tin can modem experiment puts both of those experiences together in a single project.

As [Mike Kohn] notes, this project was harder than it would seem that it should be. He actually had a much harder time getting the tin can phone part of the project optimized than getting the electronics sorted out, resulting in multiple tries with everything from the canonical tin cans to paper coffee cups before eventually settling on a pair of cardboard nut cans, the kinds with the metal bottoms. Linked together with a length of kite string — dental floss didn’t work — [Mike] added a transmitter on one end and a receiver on the other.

The transmitter used an ATtiny 2313 and everyone’s favorite audio amplifier, the LM386, while the receiver sported an electret mike preamp board, an LM566 tone decoder, and an MSP430 microcontroller. The modulation scheme was as simple as possible — a 400 Hz tone whose length varies whether it’s a one or a zero, or a stop or start bit. Connected to a pair of terminal programs, [Mike] was able to send his name over the wire string at what he calculates to be six or seven baud.

This project has all the hallmarks of lockdown boredom, but we don’t care because it’s good fun and a great learning opportunity, particularly for the young ones. There’s plenty of room for optimization, too — maybe it could even get fast enough for the Hackaday Retro 300-baud challenge.

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