Note: while this is not an exact duplicate, this question is a duplicate in that it asks where the limitation is located (software/hardware ...). So I think marking this as a duplicate is warranted, even though my question was model-specific.

I have an S9+ from Samsung and I am considering to upgrade to 512 GB or even 1 TB as it would make space for Kiwix ZIM files.

However, Samsung marketing material suggests a limit of 400 GB (i.e. 400x1000x1000x1000 Byte). This sounds arbitrary (not the usual power of two and the discrepancy between GiB and GB which may be accounted for by reserved space - in case of corruption - doesn't change that). Now, perhaps there is a technical reason that I am unaware of, but from the OS side (Linux/Android) I can't understand why there would be a limitation to 400 GB. SDXC seems to be the supported standard and should support up to 2 TiB (i.e. 2x1024x1024x1024x1024 Byte).

Is this limit simply owed to what was available around the release of the S9+ or is it an artificial limitation imposed by Samsung customizations to Android, or is there perhaps no limitation?

  • There was a question very similar to this, were the conclusion was, that the advertised maximum capacity is the capacity that is guaranteed to work and was the largest they had at the time. There are numerous phones, that advertise 16 or 32GB of maximum SD card capacity and work fine with 64 oder even 128GB.
    – GiantTree
    Commented Oct 14, 2019 at 7:09
  • @GiantTree thanks, do you happen to remember which previous question that was? I noticed plenty of other questions similar to mine, but not for the same phone model. And since these others all referred to specific phone models I didn't think anything of asking for my specific phone model. Although it wouldn't strictly be a duplicate, it might be worthwhile to mark mine and other questions as dupes of that one question you mention, because if that is the case it answers it enough to make a call as to whether one wants to buy such SD card or not. Commented Oct 14, 2019 at 8:34
  • 1
    I don't think it's about model or manufacturer, it should be a general question about the capability of SD Host Controller. If you need information about a specific device, ask the manufacturer directly that where at hardware or software level they put the limitation on SD card size, which they would never reveal. So mostly answers to such questions would be guesses, ideas or opinions. Commented Oct 14, 2019 at 11:09
  • @IrfanLatif I disagree. It stands to reason that there have been users encountering the same marketing material but they had a 512 GB microSD card around and simply tried it out. As you can tell from my question I already reasoned about the fact that the stated limitation doesn't make much sense to me. But there's always the chance I - as an individual - am missing something, which is why I turned to "the hive mind". True, no one who hasn't tried firsthand would be able to give an authoritative answer, but contacting the vendor is equally pointless (as you note yourself). Commented Oct 14, 2019 at 12:35
  • 1
    @0xC0000022L this question IIRC: android.stackexchange.com/a/129539/86358
    – GiantTree
    Commented Oct 14, 2019 at 17:41

2 Answers 2


I can now confirm that the S9+ supports a 1 TB μSD card just fine.

After a colleague had outfitted his phone with a 512 GB card, I decided to give it a try, because it was already above the limit Samsung claimed was supported but well below the limit one should expect for SDXC (see my question).

Proof of a 1 TB card working in the S9+

Edit (February 2021): Due to the other answer which appeared here, I wanted to update the screenshot and also wanted to state which model I use: Sandisk Extreme (not Extreme Pro, though).

Also note: I have meanwhile read in several places that phone manufacturers indeed specify the "supported card size" based on the SD cards available at time of the release of a phone model.


I have an S9+ and wanted to upgrade my micro sd card to a larger size. I bought a 1TB and the pictures worked fine but after a month suddenly the more recent pictures started to corrupt. Literally before my eyes my pictures in my photo gallery suddenly became grey squares and could no longer be viewed. So Samsung advertises the limit of 400GB for the S9 sd card and my experience seems to prove that it can work maybe but becomes very unstable and can stop working at any moment. I am having to get a smaller sd card. :(

  • Well, my question would be then, how comes it has worked for me will for over one year, all the while the card was/is filled "to the brim" with well over 800 GiB of data? And yes, I can access it still, oldest and new data. From experience with flash storage it seems a lot more likely you went for a "sweet deal" and the controller reported the size you expected, but the factual size is smaller. So over a certain amount new data starts overwriting old data. Of course it could also be that your card simply died on you. Commented Feb 19, 2021 at 9:55
  • I have updated the screenshot and I am stating the model of the SD card I am using. It's the same since I initially answered my own question. And as I mentioned before, it works quite fine. Even the older screenshot proved that 400 GB isn't a hard limit. The new one should prove that neither is 512 GB. So you have a colleague of mine with the same phone who proved 512 GB worked, you have me having a 1 TB card, proving it works. Don't you think you'd at least want to adjust your answer with some more information? Can a PC read and write the stated volume of the card, for example? Commented Feb 19, 2021 at 10:02
  • 1
    How about testing your card on another device, preferably a PC with an SD card reader, using a tool like h2testw? Caution: it's a destructive process, but since you're already losing data, perhaps we could establish whether your card is genuinely 1 TB (like mine) or not. Leave it running over night, it'll take ages. Commented Feb 19, 2021 at 10:07

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .