Trying to move from 128 GB microSD card to a 256 GB one

[Naki]

Using a Xiaomi Mi A1 phone with Android OS 9.0 Pie, internal flash storage being only 64 GB.
To work around the limited storage, currently a 128 GB microSD card is formatted as Internal, i.e. it is sharing storage with the built-in flash memory, allowing lots & lots of extra apps/games to be installed, while leaving space for photos/videos too.
Still, despite having plenty of storage free, it is slowly running out due to adding more photos & videos, and sometimes - more Android games for my 6-year old.

Tried to do this via a USB 3.0 SD card reader on my Windows 10 PC, but it seems Android phone/tablet SD cards formatted as Internal are not formatted to any known Windows OS file system.
I am using a Kingston reader that allows for TWO SD cards to be inserted at once - has one full size SD card slot, plus a microSD slot too.

My Windows 10 PC shows the new 256 GB card fine (it is mostly empty), but prompts to reformat the other, Android phone card. (which I cancel, of course, as it would lose all data i.e. apps/games/etc)
So, the Android phone SD card format is not any of the common FAT32, NTFS, nor exFAT.
Seems to be a customized Linux/Unix file system format, because even on Ubuntu Linux only the new 256 GB card partition shows, the other card seems to have 2 partitions on it, but my Ubuntu Linux cannot show the files on it, and does not mount it as an accessible drive.

So, is this possible at all?
Maybe a raw image format creating from OLD card then restoring that image to NEW card could work?
I will still need to change the NEW card/partition size to use all the 256 GBs though, as if not, the extra space won't be usable.

If this is possible, which approach to best use? Use Windows 10 OS, or Ubuntu Linux/etc?
OR try to do it via phone, skipping any computers?
It seems I am able to connect to the Android phone without taking card out, via WiFi -- I am using Total Commander on the PC, and Software Data Cable app on the phone, but copying from phone to a local drive on the PC is quite slow, and I am not sure even if I copy it all to my PC, how/if I could then copy it back to the NEW 256 GB card?

I am also waiting for a Android OTG USB adapter to come, maybe that could be a viable way too?

 

[thewan]

I think the only safe option is to copy out as much stuff as possible from both the internal flash and 128gb micro sd via cable connected from the phone to a computer. Then with more space on the internal flash storage and less space used on the 128gb microsd, you can migrate back to using only the internal flash storage. Then insert the 256gb microsd, migrate all your stuff again and copy back whatever stuff you removed previously.

edit: clarified abit.

 

[shovenose]

I think the only safe option is to copy out as much stuff as possible from both the internal flash and 128gb micro sd via cable connected to the phone. Then with more space on the internal flash storage and less space used on the 128gb microsd, you can migrate back to to using only the internal flash storage. Then insert the 256gb microsd, migrate all you stuff again and copy back whatever stuff you removed previously.

Yup unfortunately I believe this is your only option.

 

[Naki]

Okay, thanks guys for the replies. I will see how this works out.

IF I try the change to Portable while free Internal storage space is still NOT quite sufficient, what will happen?
Will it fail gracefully, or will it make the phone and/or some apps not working?

Will it say "Not enough Internal space to switch SD card to Portable, please free more space and try again"?
Or will it attempt the change no matter how much GBs of storage are free?

(Remember, the phone is using Android OS 9.0 Pie, thankfully no MiUI with crap apps included by default by Xiaomi, as it is an Android One/Pure device.
Only the default Google apps are present.)

Also, most of my apps - except those that do not support it - are using External memory now.
(A little bunch are Internal, as they won't allow changing to External storage.)

If I format the SD card as Portable, what happens with those apps/games?
I know ideally no apps/games should be External before I attempt this, but doing that will take a really LOT of time.
I am moving some apps/games to Internal now, and deleting the largest unused ones.
(A few games that nobody plays took 1-2, even 5 GB of space each! OUCH.. )

RE pics & videos, thankfully almost none exist, as I offloaded them recently to my Windows 10 PC when I did the change from 128 GB SD card as Portable to same card as Internal storage.