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Step-by-step code execution on the Toshiba FlashAir SD card (docs.google.com)
63 points by guedou 5 months ago | hide | past | web | favorite | 13 comments

Very good writeup, I like the documentation of the thought process and the open source tools shown in action.

What really amazed me though was both the persistence of this hacker (looks like the project took more than 3 years from first playing around to RE) and the ubiquity of the (I)TRON operatings system that‘s super hard to find anything out about, especially in light of its worldwide use.

would it be feasible to use this technique to modify the SD card so that instead of broadcasting an SSID, it attempts to connect to an SSID and (upon successful connection) pushes the contents of its filesystem to an HTTP endpoint?

i'm imagining an SD card that automatically empties itself onto my private server when i get home... rather than an SD card that i can manually access wirelessly.

The card can already do that. It can connect to an AP and you can already push files thanks to Lua.

See also the Transcend cards ( https://hackaday.com/2016/06/30/transcend-wifi-sd-card-is-a-... )

They're super easy to mess around with

Also the PQI Air Card, which is a microSD to SD adaptor!

I use it with an SD-to-microSD ribbon inside an iFlash adaptor in an iPod. That lets me share SD cards over WiFi to an iPhone.

Question - I have a device that can record video files to SD, but can't stream the it's video feed. Could I use this SD card to stream the feed to a server?

Theoretically, yes. Practically, I think you should dedicate a few months or even years to writing code to get that working... The OS is very basic, you don't get much RAM, the TCP/IP stack seems very primitive, and you don't have the source code...

There are other wireless SD cards that already run a Linux OS.

The main problem would be to figure out how your camera saves the files (it might not save them in a playable format right away - for example it could save most of the data but keep the key frames - necessary every so often - until the end or so, or do more processing on the video file only after recording is finished). Unless you reverse-engineer all that and work out a way to generate a playable stream out of the intermediate file, you’re out of luck.

You could probably get the card to live transfer the files to a server but you can’t change the filesystem so you can’t clean up which you need to do to keep recording.

These things are pretty interesting but they are quite slow/unusable in terms of transfer rate.

I wonder if that tiny antenna could be enhanced with a wire.

They're slow because the CPU is really slow, and all wifi communication needs to go via the CPU.

The antenna is unlikely to be the cause.

Is there a video of the talk somewhere ? (if that was the support for a talk)

The video will likely be online soon.

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