Booting From SD Card?

Anyone tested running the OS off an SD card?

What kind of speed differences are you seeing?

Did you run into any unforeseen pitfalls?

Which device?


I could never find the option in any ISO image writer allow that and I could never find anything in any BIOS to allow that. I wonder if it was a conscious decision? Or did I just not look hard enough?

On the other hand there are SD based “hard” drives that boot up just fine. So I wonder if it is just the SD card interface?

Etcher will write it. My first Linux was run off an SD card on a surface pro 3. Perhaps it is just you?

Most Raspberry Pi devices run off a uSD card. uSD cards are slow and prone to corruption. What’s not to like? :slight_smile:

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I’m running on Librem and using Boxes for different distros.

Boxes is still pretty buggy accessing external hard drives and peripherals via the ports.

I would like to run closer to bare metal, and have full access to peripherals via the ports. I’m hoping there might be a potential solution by running the OS off SD cards, while using the internal HD drives as storage devices. Then just popping in the SD card for the distro I need to run.

I’ve haven’t tested it yet. Some say it would be faster. Others say it’s magnitudes slower.

The good news is that it won’t cost you much money to give it a try.

Not every boot environment will necessarily support booting from SD. However if you have an SD card reader USB dongle, you may work around that limitation, if the limitation exists.

Gotta love the Linux community: Distros made to run of USB and MicroSD cards ->

…Try getting that from the evil Apple or Microsoft cartels.

Slax is interesting. If you plug usb with your slax on it into any other PC/device from orginial, would it still work and run just the same (whether it boots on legacy, uefi, different boards/bios) or do you have to configure every time you do?

Had a buddy that worked as a supervisor at linkedin. They swapped out hundreds of SD drives a week based on lifetime read/write estimates as a full time job. Not based on failures, but on engineering estimated half-life. (I guess larger cloud services must be more.)

one thing i’ll say. encryption is SLOW.

NEVER encrypt what you don’t need to encrypt … use GPT and multiple partitions or local encrypted dir/files to encrypt if you need versatility.

if you keep your /home together on the same partition as the OS files make sure it’s not larger than it has to be. 32 GB does the job okay for me … rest is what you partition and format yourself … plenty guides for that around (both CLI and GUI)

lastly. you can partition everything as ‘unformated’ during clean install from LIVE iso so you do NOT need to do everything at once. carefull how you mount …


On the Mac I used to boot right off a Samsung T5 SSD. I’d define the startup disk through OSX. If the T5 was plugged in, it would boot into the T5.

I didn’t notice any speed differences. T5 might have been faster. No issues with encryption that I could tell.

Is the slow encryption due to the SD card?

If I went with a T5 plugged into a USB3 port on Librem, then used Pureboot to boot to the USB, could I get the functionality and speed I get now, operating off the T5?

I’ve booted about 10 different distros from SD card on the Pinephone, which came with PostMarketOS installed on the eMMC. It’s worth noting that I’ve never booted PMOS from sd, so I can’t make a direct comparison, but booting from sd doesn’t seem much slower. It does seem to be significantly slower to start applications, however. Still, I use Mobian on sd every day (because I like it) and remove the sd to boot/update PMOS once a month (to see if it has improved).

Bad advice. Encrypt everything, because eventually you will leave something unencrypted that should be encrypted, and get in trouble. You might then regret going for speed.

Moreover, encryption is not slow if your CPU is faster than the medium, so on an SD card you will never notice.


Yes but the T5 (now superseded by the T7?) is a sweet drive. Yes if you want to boot from an external SSD like the T5 then performance will be solid (not as good as an internal NVMe drive but still good). However if you have a lot of different operating systems to try, this will get somewhat expensive.

If money is not a major consideration then using a good spec external SSD (like the T5) will be vastly superior to an SD card.

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On OSX I simply installed the OS to the external drive & then set it as the startup drive.
I’m searching around for how to best do this on Linux. The recommends are Etcher or Rufus to make an external drive bootable.

Isn’t there a more direct way to do this, that wouldn’t add a step to the boot up process?

It depends on what (source) operating system you are starting with, what hardware you have and what (destination) operating system you are trying to boot externally.

First and foremost, I would follow the recommendation of the destination operating system that relates to the source operating system.

With source operating system Linux and destination operating system Linux (specifically in my case Ubuntu),

  • download .iso (verify!)
  • use Startup Disk Creator to convert the .iso file onto an external drive (A)
  • boot from drive A
  • choose option to install operating system and install onto external drive (B) - be careful during install to make sure that the install is onto the correct external drive and also not onto the internal drive

You can recycle drive A once you have finished the above steps and then use it for the next .iso

Drive A can be as simple as a, say, 8 GB flash drive - whereas drive B would need to be a decent external SSD (like a T5).

At the end of that process, repeated for each .iso, you will have one external SSD for each .iso and you can simply choose an external SSD, plug it in and use the boot disk menu to choose to boot from the external SSD (and maybe you can make that choice permanent).

When I did that with Fedora, it worked exactly this way.

And the tape relay stations do not need to decrypt, they only need the traffic to pass through as it came.

the tape relay stations ? wait. i though we were talking about a local only boot process or some files being transferred locally from one encrypted medium to the next encrypted medium (LUKS) in my case.

that’s why i said that to ME , a transfer from SATA3 encrypted LUKS SSD (external) to SATA3 encrypted LUKS SSD (internal , m2) is SLOW compared to non encrypted mediums (or at least one of them non-encrypted). perhaps this is only a weird quirk with WD drives. i’ll test when i can with my Shangsungs to see if it’s the same (probably NOT since NVME is faster than SATA3. external or not … )