Write protect a micro sd? | Bitcointalksearch.org

ABCbits

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Quote from: jackg on December 14, 2018, 01:47:25 PM

Maybe I’m being overprecautious but I was just wondering if anyone had a way to do it that they know of?

If we're talking about theory or something that only expert could do, then modify the firmware of the microSD is the answer. write good blog post about this topic. But basically, at least you need :
1. Both software and hardware to modify microSD firmware
2. Low-level programming knowledge
3. Knowledge how microSD works, to the low-level/hardware-level

And you're too overcautious, if you can secure your device or OS properly, then it should be ok acceptable.

jackg

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https://bit.ly/387FXHi lightning theory

Thanks, you all finally answered my question and returned NO.

So now I’ll just destroy the device I use instead or just won’t bring it online...

bob123

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Quote from: jackg on December 14, 2018, 01:47:25 PM

It is on a micro sd card not an sd card I know of the buttons of ad cards already and I have already said I want to know if there’s something similar on hardware level to that, I don’t know what there isn’t to understand???

The switch of SD cards is not hardware level at all. It doesn't protect anything from being written onto the SD. It is just a flag which says "please dont write, regard this as read-only".
Each program / OS can decide whether to follow this or not.

You still didn't answer my question. What do you want to achieve with the write protected SD card ?
Write protect against WHO or WHAT ?

You CAN NOT protect an SD card from being written onto on a hardware level. This is technically NOT possible. You would need to use a writeblocker between your computer and the SD card to access it as 'write protected'.

Therefore.. WHY do you want it to be write-protected ? What is the exact reason ?

This seems to be a XY problem.

jackg

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https://bit.ly/387FXHi lightning theory

I want to do it on hardware level yes. So nothing gets saved while in that read only mode.

I don’t care about someone intelligently coding something because I’ll completely erase everything straight after (cleaning the oartition table and making a new one that sets everything to zero).

Maybe I’m being overprecautious but I was just wondering if anyone had a way to do it that they know of?

It is on a micro sd card not an sd card I know of the buttons of ad cards already and I have already said I want to know if there’s something similar on hardware level to that, I don’t know what there isn’t to understand???

KingZee

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Quote from: bob123 on December 13, 2018, 02:15:59 AM

He clearly mentioned he wants to do it on a hardware-level, exactly 2 posts above yours:

I know!

Did you check the link I shared?

It's just painstakingly more effort. So I explained to him that if in the end he decides to do it on a software level, the limitations he's going to go through.

And even if he does change it on a hardware level, in the end, it could still be formatted.

So what solution he chooses is going to depend on his usecase. I he afraid his sd card is going to be intentionally tampered with? Sure, try hardware-level. Does he know the sd card is going to be with him at all times? Or is it somewhere where no one will intentionally try to mess with it? Software-level would probably be fine and prevent himself from making any unintentional mistakes..

But yeah like you said, depending on what he wants to achieve he could go for different solutions

bob123

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Quote from: KingZee on December 12, 2018, 03:42:37 PM

[...] it's really hard to achieve what you want to achieve on a software level. No matter what you try to do software-wise, any knowledgable user is going to be able to change the permissions on the files of your sd-card.

He clearly mentioned he wants to do it on a hardware-level, exactly 2 posts above yours:

Quote from: jackg on December 12, 2018, 04:26:01 AM

I’m trying to do it hardware level [...]

OP, just to make sure:
Are you trying to protect it that the user on your system won't be able to 'accidentally' (or maliciously) write to your sd card ?
Or do you want to protect the sd card that way, that noone will ever be able to write onto that sd card again ?

Some SD cards do have a switch which basically is a flag that tells the system that this is in read-only mode.
However, the system decides itself if it follows this convention or not.

On a hardware level, there is nothing you can do to truly protect your sd card from being written onto.
You could use a write-blocker and always access this sd card via a write blocker.
In this case there won't be a possibility to write onto it. But taking the sd card out and plugging it into a linux will still allow to write onto it.

The correct approach fully depends on what you want to achieve.

May you explain what EXACTLY you want to achieve ?

KingZee

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Quote from: jackg on December 12, 2018, 04:26:01 AM

So it seems there isn’t a way to do it then?

I’m trying to do it hardware level so a seed doesn’t end up being stored anywhere on that drive.

I tried to fiddle around as much as I could, found this funny interesting gem Cheesy

:

https://hackaday.com/2014/01/18/the-tiniest-sd-card-locker/

No idea if that thing is effective, the comments are very interesting too! But regardless, it's really hard to achieve what you want to achieve on a software level. No matter what you try to do software-wise, any knowledgable user is going to be able to change the permissions on the files of your sd-card.

If you're sure that no one else will have access to it, or if anyone that will have access won't have a reason to overwrite the files, then you can go ahead and just write lock it using linux/windows. You should probably know that even if you make the SD card read-only, it could still be completely re-formatted.

LoyceV

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Quote from: jackg on December 12, 2018, 04:26:01 AM

I’m trying to do it hardware level so a seed doesn’t end up being stored anywhere on that drive.

I would use the LIVE Linux on your laptop. My favourite is Knoppix from DVD. Assuming you have 8+ GB RAM, start it with command line options:

Code:

knoppix64 toram

Then remove the DVD.
Being paranoid, I prefer to kill all networking and swap too:

Code:

swapoff -a
ifconfig wlan0 down
ifconfig eth0 down

Then copy the required files from a USB-stick to the home directory (in RAM), remove the stick, and work your magic. Configure your printer from your browser by going to localhost:631.

jackg

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https://bit.ly/387FXHi lightning theory

So it seems there isn’t a way to do it then?

I’m trying to do it hardware level so a seed doesn’t end up being stored anywhere on that drive.

Pmalek

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In Windows 10 you can password protect your hard drives, usb sticks and even sd cards with BitLocker which comes with the OS. Just right click on the drive and Turn BitLocker On. But I am not sure how that would work in a non Windows environment and would you be able to unlock the drive with your password outside of Windows.

BitMaxz

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You can try the sd adapter for microSD it also has the switch where you can enable the write protection. Never tried this but I have microSD card with write protection before and if I use the sd adapter and use the switch to disable it and now it works and I can put any file without write protected so maybe it would work if you use an SD adapter.

Another method that I know you can enable the write protection is by using diskpart tool through CMD but you can do this with windows OS take a look at this method if ever you need it Enable or Disable Disk Write Protection in Windows

jackg

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https://bit.ly/387FXHi lightning theory

Sd cards have switched, my microsd card doesn’t seem to? I want to do 14 of 15 multisig. I’ll print the keys off on an offline printer and also write them down and keep them on a flash drive.

Anyone know of the best way to do this, the micro sd will be going into a rapsberry pi. I can use live Linux on my laptop, but I’d rather not...

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