Dumping the Vita NAND

When we last left off, I had spent an excess of 100 hours (I’m not exaggerating since that entire time I was working, I listened to This American Life and went through over a hundred one-hour episodes) soldering and tinkering with the Vita logic board to try to dump the eMMC. I said I was going to buy a eMMC socket from taobao (the socket would have let me clamp a eMMC chip down while pins stick out, allowing the pressure to create a connection) however, I found out that all the sellers of the eMMC socket from taobao don’t ship to the USA and American retailers sell the sockets for $300 (cheapest I could find). So I took another approach.

Packet Sniffing

My first hypothesis on why it is not working is that there’s some special initialization command that the eMMC requires. For example, CMD42 of the MMC protocol allows password protection on the chip. Another possibility was that the chip resets into boot mode, which the SD card reader doesn’t understand. To clear any doubts, I connected CLK, CMD, and DAT0 to my Saleae Logic clone I got from eBay.

Vita eMMC points connected to logic analyzer.

Vita eMMC points connected to logic analyzer.

As you can see from the setup, I had the right controller board attached so I can get a power indicator light (not required, but useful). I also took the power button out of the case and attached it directly. The battery must be attached for the Vita to turn on. Everything is Scotch-taped to the table so it won’t move around. Once all that is done, I captured the Vita’s eMMC traffic on startup.

First command sent to eMMC on startup

First command sent to eMMC on startup

After reading the 200 paged specifications on eMMC, I understood the protocol and knew what I was looking at. The very first command sent to the Vita is CMD0 with argument 0×00000000 (GO_IDLE_STATE). This is significant for two reasons. First, we know that the Vita does NOT use the eMMC’s boot features. The Vita does not have its first stage bootloader on the eMMC, and boots either from (most likely) an on-chip ROM or (much less likely) some other chip (that mystery chip on the other side maybe?). Second, it means that there’s no trickery; the eMMC is placed directly into Idle mode, which is what SD cards go into when they are inserted into a computer. This also means that the first data read from the eMMC is in the user partition (not boot partition), so the second or third stage loader must be in the user partition of the eMMC. For the unfamiliar, the user partition is the “normal” data that you can see at any point while the boot partition is a special partition only exposed in boot mode (and AFAIK, not supported by any USB SD card reader). Because I don’t see the boot partition used, I never bothered to try to dump it.

Dumping

I tried a dozen times last week on two separate Vita logic boards trying to dump the NAND with no luck. Now that I’m on my third (and final) Vita, I decided to try something different. First, I did not remove the resistors sitting between the SoC and eMMC this time. This is because I wanted to capture the traffic (see above) and also because I am much better at soldering now and the tiny points doesn’t scare me anymore. Second, because of my better understanding of the MMC protocol (from the 200 page manual I read), I no longer attempted to solder DAT1-DAT3 because that takes more time and gives more chance of error due to bad connections. I only connected CLK, CMD, and DAT0. I know that on startup, the eMMC is placed automatically into 1-bit read mode and must be switched to 4-bit (DAT0-DAT3) or 8-bit (DAT0-DAT7) read mode after initialization. My hypothesis is that there must be an SD card reader that followed the specification’s recommendation and dynamically choose the bus width based on how many wires can be read correctly (I also guessed that most readers don’t do this because SD cards always have four data pins). To test this, I took a working SD card, and insulated the pins for DAT1-DAT3 with tape. I had three SD card readers and the third one worked! I know that that reader can operate in 1-bit mode, so I took it apart and connected it to the Vita (CLK, CMD, DAT0, and ground).

As you can see, more tape was used to secure the reader.

As you can see, more tape was used to secure the reader.

I plugged it into the computer and… nothing. I also see that the LED read indicator on the reader was not on and a multimeter shows that the reader was not outputting any power either. That’s weird. I then put a working SD card in and the LED light turned on. I had an idea. I took the SD card and insulated every pin except Vdd and Vss/GND (taped over every pin) and inserted the SD card into the reader. The LED light came on. I guess there’s an internal switch that gets turned on when it detects a card is inserted because it tries to draw power (I’m not hooking up Vdd/Vss to the Vita because that’s more wires and I needed a 1.8V source for the controller and it’s just a lot of mess; I’m using the Vita’s own voltage source to power the eMMC). I then turned on the Vita, and from the flashing LED read light, I knew it was successful.

LED is on and eMMC is being read

LED is on and eMMC is being read

Analyzing the NAND

Here’s what OSX has to say about the eMMC:

Product ID: 0×4082
Vendor ID: 0x1e3d (Chipsbrand Technologies (HK) Co., Limited)
Version: 1.00
Serial Number: 013244704081
Speed: Up to 480 Mb/sec
Manufacturer: ChipsBnk
Location ID: 0x1d110000 / 6
Current Available (mA): 500
Current Required (mA): 100
Capacity: 3.78 GB (3,779,067,904 bytes)
Removable Media: Yes
Detachable Drive: Yes
BSD Name: disk2
Partition Map Type: Unknown
S.M.A.R.T. status: Not Supported

I used good-old “dd” to copy the entire /dev/rdisk2 to a file. It took around one and a half hours to read (1-bit mode is very slow) the entire eMMC. I opened it up in a hex editor and as expected the NAND is completely encrypted. To verify, I ran a histogram on the dump and got the following result: 78.683% byte 0xFF and almost exactly 00.084% for every other byte. 0xFF blocks indicate free space and such an even distribution of all the other bytes means that the file system is completely encrypted. For good measure, I also ran “strings” on it and could not find any readable text. If we assume that there’s a 78.600% free space on the NAND (given 0xFF indicates free space and we have an even distribution of encrypted bytes in non-free space), that means that 808.70MB of the NAND is used. That’s a pretty hefty operating system in comparison to PSP’s 21MB flash0.

What’s Next

It wasn’t a surprise that the eMMC is completely encrypted. That’s what everyone suspected for a while. What would have been surprising is if it WASN’T encrypted, and that tiny hope was what fueled this project. We now know for a fact that modifying the NAND is not a viable way to hack the device, and it’s always good to know something for sure. For me, I learned a great deal about hardware and soldering and interfaces, so on my free time, I’ll be looking into other things like the video output, the mystery connector, the memory card, and the game cards. I’ve also sent the SoC and the two eMMC chips I removed to someone for decapping, so we’ll see how that goes once the process is done. Meanwhile, I’ll also work more with software and try some ideas I picked up from the WiiU 30C3 talk. Thanks again to everyone who contributed and helped fund this project!

Accounting

In the sprit of openness, here’s all the money I’ve received and spent in the duration of this hardware hacking project:

Collected: $110 WePay, $327.87 PayPal, and 0.1BTC

Assets

Logic Analyzer: $7.85
Broken Vita logic board: $15.95
VitaTV x 2 (another for a respected hacker): $211.82
Rework station: $80
Broken 3G Vita: $31
Shipping for Chips to be decapped: $1.86

Total: $348.48 (I estimated/asked for $380)

I said I will donate the remaining money to EFF. I exchanged the 0.1BTC to USD and am waiting for mtgox to verify my account so I can withdraw it. $70 of donations will not be given to the EFF by the request of the donor(s). I donated $25 to the EFF on January 10, 2014, 9:52 pm and will donate the 0.1BTC when mtgox verifies my account (this was before I knew that EFF takes BTC directly).

Updates on the Vita Hardware Hacking project

After a week of trying to dump the eMMC (spoilers: didn’t happen yet), I’ve decided to post this update about things I’ve tried to do (and how I tried to do it) and where the money is going to.

Supplies

I had two Vita logic boards. The first one, which I removed the SoC and eMMC to find the trace points (shown previously), came from eBay. The second board came from a Vita with a broken screen generously donated by @Amxomi. I also bought a professional rework station, the X-Tronic 4040 which was paid partially by your donations (I returned the heat gun) and partially thanks to wololo. For wiring, the thinnest wire I could find is enamel-coated magnet wire. For soldering the wires, I got 60/40 Rosin solder and a Rosin flux pen.

Attempt One

The first thing I did was remove the EMI shield base blocking the test point resistors. With the reflow station’s hot air gun, it was much easier than the heat gun I used last time. Next I warmed up my soldering skills by hooking wires up to a microSD to SD card adapter. My plan was to attach the wires to the test point and plug the SD card into a SD card reader. To expose the copper in the enamel-coated wire, I melted a blob of solder and kept it on the tip of the iron at 400C. Then I dipped the tip of the wire into the liquid solder, which both coats the tip of the wire with solder and also removes the coating. It’s a neat trick that I used all the time throughout the rest of the ordeal.

Then I brushed the pins of the microSD adapter with flux and quickly melted a small blob of solder on each pin. Then with a pair of tweezers, I held each wire next to the pin, and as soon as it is heated, the small bit of solder on the wire joins with the blob on the pin and they connect.

It gets much harder connecting the other end. There is very little exposed solder on the tiny resistors, and it is very hard to add more because you might accidentally short circuit two adjacent pads. I made sure there is a bit of solder on the end of the wire using the trick. Then I held the end of the wire steady with the tweezer while tapping it with the iron. It takes many tries for it to stick on, and many times when trying to attach the neighboring pads, the heat from the iron loosens the other wires. In addition, accidentally bumping into the wire causes enough stress to rip the solder off the resistor (because there is so little solder), so I just taped everything to a piece of cardboard. I also can’t test if my joints are correct and not shorted with any other joints because of how small and close everything is.

After a couple of hours, the wires are soldered to the points but there are a couple of problems. First, as mentioned, I couldn’t test the correctness of my connections. Second, I don’t know if in the process of soldering to the tiny resistors, I damaged any resistors and if so, would it still work. Third, I never found a test point for Vdd because for some reason, Vdd shorts to Vss/Ground on my first board. As expected, after plugging the microSD adapter into a reader into the computer, nothing shows up. Because there could be so many problems, I removed all the wires and started over.

Attempt Two

First, I located a test point for Vddf (Vdd is power to the eMMC controller while Vddf is power to the actual NAND chip). My hypothesis is that the same power source that powers Vddf also powers Vdd (although the Samsung documents recommends against this). This point is on top of the tiny resistor to the left of the audio jack.

Next, I decided to remove all of the 150ohm resistors on the test points in order to get more solder surface area. Looking at the eMMC testpoints picture from last time, it’s important to note that the pad on the left of each resistor is the one coming from the eMMC while the pad on the right of each resistor is the one going to the SoC. The resistors themselves may be for current limiting or noise removal. Removing them is as simple as pointing at it with the hot air gun set to 380C for half a minute and then using tweezers to to remove them.

I also found it easier to solder wires directly to the SD card reader instead of to an microSD to SD card adapter. I first verified that the card reader still works and that my wires are not too long by soldering the other end of the wire directly to an old 128MB SD card. After verifying, I removed the wires from the SD card and attached them to the now exposed test points.

Unfortunately, it still didn’t work. The computer sees the SD card reader but believes no card is inserted. Again, there could be any number of problems including (still) bad soldering, Vdd not receiving power, or even read protection in the eMMC.

Attempt Three

Next I made another attempt to find Vdd. The problem is that my multimeter shows a short from Vdd to Vss. This means that Vdd is somehow shorted to ground either because I broke something with all the heat and bad soldering or because that is by design (which I don’t think is true because all documents I read say that you need to power Vdd for the eMMC controller to work). I thought maybe I can experiment by sending test voltages through various locations on the first logic board (the one with the chips removed) and see if I get a voltage drop in the Vdd pad. I used an old broken MP3 player as my voltage source (since it was just laying around and I didn’t want to buy a power supply, rip open any working cable/device, or solder to a battery). I attached the positive end to a pointed screwdriver and the negative end to the Vita’s ground. Then I attached one probe of my voltmeter to the same ground. Then with the screwdriver in one hand and the voltmeter probe in the other hand, I tried to send voltage through every location on the board. Unfortunately, the only response was sparks on capacitors here and there but no response in Vdd.

Back to the second Vita, I tried to attach the battery and charger and turned it on. At first, I got excited and saw a voltage drop on the eMMC’s decoupling capacitor (meaning there’s power going to the eMMC). However, after going back and reattaching the wires, I could no longer reproduce the result. In addition, the power light no longer responds to the power switch. I believe that I shorted something and the first time I powered it on, it destroyed some component; so the next time I attempted to power it on, it fails before even attempting to power the eMMC.

Regardless, I tried to reattach all the wires with better soldering on the assumption that my only problem is still the bad soldering (likely not true). Being the fourth or fifth time doing this, I am getting better at soldering these extremely tiny points. My trick was to first align the wire to the board and then using the tweezer, make a 90 degree bend on the end of the wire. This makes the end of the wire the same length as the original resistors. Then I quickly dip the end in solder, flux the board, and attach the wire to two pads instead of one. This makes a stronger connection. Even though I did a much better job and soldering the test points, I still could not get anything to show up on my computer.

Attempt Four

Now that I have experience in soldering tiny points, I made an attempt at soldering directly to the eMMC removed from the first Vita. However, after a quick test (nothing shows up on the computer), I didn’t look any farther because I believe that the eMMC must be part of a circuit of capacitors and resistors in order for it to work (and not break the chip). All documents I’ve read supports this.

I also made yet another attempt at resoldering to the board again and still no luck. At this point, I believe that either I still am not powering Vdd correctly, or I broke the eMMC at some point. I also suspect that perhaps my SD card reader does not support the Samsung eMMC or that it is not being initialized correctly.

What’s Next

I still haven’t given up. I will continue to try resoldering the points. I still want to find a way to surely power Vdd; I bought another Vita from eBay because I believe the second Vita is now broken. I also ordered a eMMC socket with the last of the usable donations, but it will take at least a month to arrive from China. There’s also the possibility that the eMMC does something unsupported by my SD card to USB adapter and I want to do some raw signal interaction with an Arduino. If you want live updates of progress as I’m working, join #vitadev on EFnet.