How to split a 256gb micro sd into multiple smaller partitions?

How to split a 256gb micro sd into multiple smaller partitions?

Aug 14, 2019 at 12:36 AM
Hi, I have a question that I can't seem to find an answer to online.
I have a micro SDHC that is 256gb, that only ever reads as 4mb. I have used Etcher to burn a Raspbian image onto it, and Etcher recognized it as 256gb. However, on Windows 8 it's still 4mb. (Raspbian wouldn't boot - maybe there's a gb cieling, however not relevant to my needs.

What I am specifically interested in, is if I can do anything to make it appear as 2 smaller 128gb cards, or maybe even 4 64gb cards, possibly with some kind of partition scheme.

Please realize I have no clue how these work, or if a device that has a size limit on the sdhc's can even physically read a card that has been partitioned into smaller parts, I am simply looking for a method to do it. Otherwise, this probably expensive card is completely useless.

Thank you for your time.
(also not sure where the right place to ask this is, sorry if I've done something wrong.)

## It appears I wasn't completely clear, sorry for the confusion.
I have no intention of using this 256gb sdhc with my Raspberry Pi.

My issue is, that no matter if I use Gparted or format with Windows, the card will only ever read as 43mb.

I can confirm it read as 43mb before I ever even wrote Raspbian to it.

When I did so, Etcher read it as a 256gb, and warned me that it was unusually large. It failed each time I tried, for some reason.

I am concerned that this sdhc is a fake, after all I did not purchase it (my parents bought it, and sold me the computer it was in) and no matter what I use it only ever reads as 43mb.

I was asking about the partitions, because I was wondering if it was possible to bypass memory limits with certain devices, by having say 4 64gb partitions for a device only supporting 64gb sd's, etc.

Sorry I was not more clear.

» 5 Answers

  • Tom Bombadildo Best answer
    Aug 16, 2019 at 2:34 AM
    Keep in mind @PityOnU is actually wrong about the max card size a Pi can use, the Pi can support any micro SD card size you want without issue.

    While it will only boot from FAT32 (which Windows will cap at 32gb, but you can actually have a 2TB partition if you wanted), you can simply setup a small FAT32 partition (usually 64MB) for boot, and then have the entire rest of the card be exFAT for the OS files. This is what all modern Pi images do these days. I have a 200gb msd card that I've used in my Pi 2->Pi 4 without issue, ever.

    In regards to your question, you could partition the card as many times as you'd like, however keep in mind when you write an image to an SD card for the Pi, it overwrites the entire card and it's partitions. You would need to do so after setting up your Pi, and likely while using whatever Pi distro you use to avoid breaking boot. (Though you could probably get away with using any Linux distro, but j wouldn't trust Windows to do it, it will most likely break something).
  • Hayato213
    Aug 14, 2019 at 12:39 AM
    What show up is only the boot partition from the image that you burn on to the sd card, not the whole card when you plugged in.
  • MicmasH_Wii
    Aug 14, 2019 at 12:47 AM
    I do understand that, however you gave me an idea. Before I ever put raspbian on it, it would still say the same thing (I misremembered ; it's 43 mb, not 4... not relevant though.)
    I have a feeling it was partitioned wrong to begin with, however I'm still wondering if I can get it to read as multiple seperate cards, if possible.
  • PityOnU
    Aug 14, 2019 at 12:50 AM
    Assuming you are putting this on a Pi (Rasbian, and all) - the Pi has a limit of 32GB for its card slot. Your card is indeed unsupported by the platform.

    Regarding your partitioning, you can erase all partitioning data on the disk from within Windows by using "clean" command in the venerable "diskpart" utility.

    After you clean all of the old partitioning data off of there, you can use "Computer Management" to easily intialize and partition the disk as you please from within WIndows.
  • MicmasH_Wii
    Aug 16, 2019 at 10:05 PM

    It's not a fake, I used Etcher to burn a really small image to it (single partition, it's the freedos floppy .img) and used Windows to format, and now it is reading as 256gb!

    I will try to partition it, and if it works the way I think it is, hey it's answered! Thank you all so much.