Long rant ahead.. 5k characters pretty much completely used. So feel free to have another cup of coffee and have a seat 🙂

So.. a while back this flash drive was stolen from me, right. Well it turns out that other than me, the other guy in that incident also got to the police 😃

Now, let me explain the smiley face. At the time of the incident I was completely at fault. I had no real reason to throw a punch at this guy and my only "excuse" would be that I was drunk as fuck - I've never drank so much as I did that day. Needless to say, not a very good excuse and I don't treat it as such.

But that guy and whoever else it was that he was with, that was the guy (or at least part of the group that did) that stole that flash drive from me.
Context: https://devrant.com/rants/2049733 and https://devrant.com/rants/2088970

So that's great! I thought that I'd lost this flash drive and most importantly the data on it forever. But just this Friday evening as I was meeting with my friend to buy some illicit electronics (high voltage, low frequency arc generators if you catch my drift), a policeman came along and told me about that other guy filing a report as well, with apparently much of the blame now lying on his side due to him having punched me right into the hospital.

So I told the cop, well most of the blame is on me really, I shouldn't have started that fight to begin with, and for that matter not have drunk that much, yada yada yada.. anyway he walked away (good grief, as I was having that friend on visit to purchase those electronics at that exact time!) and he said that this case could just be classified then. Maybe just come along next week to the police office to file a proper explanation but maybe even that won't be needed.

So yeah, great. But for me there's more in it of course - that other guy knows more about that flash drive and the data on it that I care about. So I figured, let's go to the police office and arrange an appointment with this guy. And I got thinking about the technicalities for if I see that drive back and want to recover its data.

So I've got 2 phones, 1 rooted but reliant on the other one that's unrooted for a data connection to my home (because Android Q, and no bootable TWRP available for it yet). And theoretically a laptop that I can put Arch on it no problem but its display backlight is cooked. So if I want to bring that one I'd have to rely on a display from them. Good luck getting that done. No option. And then there's a flash drive that I can bake up with a portable Arch install that I can sideload from one of their machines but on that.. even more so - good luck getting that done. So my phones are my only option.

Just to be clear, the technical challenge is to read that flash drive and get as much data off of it as possible. The drive is 32GB large and has about 16GB used. So I'll need at least that much on whatever I decide to store a copy on, assuming unchanged contents (unlikely). My Nexus 6P with a VPN profile to connect to my home network has 32GB of storage. So theoretically I could use dd and pipe it to gzip to compress the zeroes. That'd give me a resulting file that's close to the actual usage on the flash drive in size. But just in case.. my OnePlus 6T has 256GB of storage but it's got no root access.. so I don't have block access to an attached flash drive from it. Worst case I'd have to open a WiFi hotspot to it and get an sshd going for the Nexus to connect to.

And there we have it! A large storage device, no root access, that nonetheless can make use of something else that doesn't have the storage but satisfies the other requirements.

And then we have things like parted to read out the partition table (and if unchanged, cryptsetup to read out LUKS). Now, I don't know if Termux has these and frankly I don't care. What I need for that is a chroot. But I can't just install Arch x86_64 on a flash drive and plug it into my phone. Linux Deploy to the rescue! 😁
It can make chrooted installations of common distributions on arm64, and it comes extremely close to actual Linux. With some Linux magic I could make that able to read the block device from Android and do all the required sorcery with it. Just a USB-C to 3x USB-A hub required (which I have), with the target flash drive and one to store my chroot on, connected to my Nexus. And fixed!

Let's see if I can get that flash drive back!

P.S.: if you're into electronics and worried about getting stuff like this stolen, customize it. I happen to know one particular property of that flash drive that I can use for verification, although it wasn't explicitly customized. But for instance in that flash drive there was a decorative LED. Those are current limited by a resistor. Factory default can be say 200 ohm - replace it with one with a higher value. That way you can without any doubt verify it to be yours. Along with other extra security additions, this is one of the things I'll be adding to my "keychain v2".