Autodetection of large drives fails on Linux

[fhunleth]

The user is programming a 120 GB SSD connected via a SATA->USB3 cable using fwup. The drive is not being autodetected since fwup thinks that it's too large to be a memory card. There should be a better way of detecting removable drives or the user should be given an error that's more helpful.

[jclif]

I believe I'm having a similar problem on MacOS.

[fhunleth]

@jclif Could your drive be failing one of these size checks: https://github.com/fhunleth/fwup/blob/master/src/mmc_osx.c#L103-L110

[jclif]

Yupyup, I have a rather large SD card (>120 GB); though by modern standards, cards of this size seem to be more and more common.