Tue Oct 03, 2017 1:07 am
You can expand (or otherwise alter) partitions on the SSD using gparted. But since a mounted partition can't be changed, you have to boot from some other device and unmount the drive and/or partitions you want to work on. This can be done within gparted. Fortunately, if a Pi has an SD card in the slot, it will look there first to boot before looking for a bootable USB device. Therefore, boot to an SD card, then modify the partitions on the SSD as needed. Once the SSD is configured to your satisfaction and contains both a boot partition and a root partition, so long as you have the "boot from USB" OTP bit set, shut down the Pi3B, remove the SD card, and then boot the Pi from the SSD.