I have a Western Digital external HDD that contains two partitions: one formated in ext4 for my laptop backup (Arch Linux), and one formated in exFAT for storing media files that I use across different operating systems.

I want to read directly on my Pixel 6a (GrapheneOS) the files stored on the exFAT partition. However, when I plug the drive through the USB A to C adapter (sold with the phone), GOS views the drive as a SD card and asks me to format it in order to use it.

I though exFAT support was included in the Linux kernel since 5.10 (I run 5.10.194-android13-4-g290eb1d8e5b9) and worked out of the box.

Why the phone can’t recognize it? What can I do about it (I don’t want to format it)?

5 months later

I fixed it.

I used fdisk on Linux to partition the disk in the first place. However, it sets the partition type by default to Linux. Hence, my exFAT partition was not recognized as such. After changing to HPFS/NTFS/exFAT type (code 07), it is correctly recognized on my Pixel!

10 months later