I currently have a Sony Z1 Compact. Unfortunately, it has an unlockable bootloader. I typically install Cyanogen on my android devices, but in this case, I don't have that option (without messing around with packages and changing out some kernels and so-fourth which I don't want to deal with).
I'm running the stock Sony 5.1 firmware with SuperSU root. My SDCard from my old phone is formatted in ext4. Upon loading it into the Sony Z1, it tells me the card is "damaged" (it doesn't recognize ext4) and refused to mount it. I can mount it via adb manually using the following:
mount -t ext4 /dev/block/mmcblk1p1 /storage/sdcard1
But of course, it doesn't show up as mounted storage in any Android app or the system preferences. I've found a myriad of posts for older 4.4 firmware references files that don't seem to exist in Android 5.1 (at least not on the Sony firmware).
The kernel obviously supports ext4. I can mount it. What is the correct way to get the Sony firmware to either auto-mount it or to setup my device to mount it manually on boot and have it correctly recognize it as an external sdcard to all my other android apps.
It's a 128GB card filled with my music (well, A through W. X through Z will have to wait until I decide to buy a bigger card) and I really don't want to have to reformat it in vfat.