SD card wrong space

[z4v4l]

Installing, say, Ubuntu on a disk that already contains Windows usually works fine. There is a risk of course, any time you move around or resize partitions. Make sure you have a backup.

linux support for NTFS is unreliable and it's not advisable to touch NTFS volumes of your Windows PC, containing the OS and your data from linux.

There is nothing wrong with using the SD card elsewhere. Just use it with systems that can handle the file system that's on the card.

It's practical to do the same with USB memory sticks - install a live linux image to it, and then use the card for both storage and as a generic boot stick. Both types of devices are just block devices and you can use any partition type and file system type(s) you'd like on them.

have you read what I wrote? It's not the same as with USB sticks or even close relatives - eMMC modules, because SD cards internal controllers may expect the one FAT volume with MBR partitioning scheme setup to operate on the card properly. It's because this is a requirement of the SD card specification. the fact, SD cards work with partitioning setups, different from what is required in the spec, is just a happy coincidence. Still, in these scenarios, cards may operate suboptimally and have less wear protection etc. I have faced cards, refusing to work with ext4 and coming back to normal behaving citizens after reformating them to FAT.
Also, since the image flashed on the card is for using as a "boot volume" for Pinephone, even accessing it from a linux PC - meaning modifying something there, without much of understanding, may make it unusable as a boot volume. of course, just putting there some pics or changing what you are really sure about, won't hurt, but generally, it's better to insert it into a target device after flashing and then transfer needed data to that storage by the known means - ftp, ssh etc. think of it as a hard drive of a PC. once you installed an OS there, you won't be putting it into another machine. unless you have some strong reasons or thirst for adventures.