I have recently bought a new ssd of 120 GB, and I ended up format it to FAT filesystem, then later I flashed raspbian jessie onto it. Everything went well and is booted from SSD until I hit expand filesystem that messed up OS installation.
Then I put back my old SD card and and booted from it. With SSD connect ed to USB , I went /boot folder on USB SSD It was empty. And SSD is identified as fat when booted from SD Card. The question is does formatting SSD with FAT is okay or acceptable? Or formatting SSD to ext4 would have made more sense which could have helped filesystem expansion?