Picked up a whole bunch of these the other day. I got 4.20.2F operational and in testing right now:
localhost#show ver
Arista DCS-7050QX-32-R
Hardware version: 02.11
Serial number: XXXXX
System MAC address: XXXXX
Software image version: 4.20.2F
Architecture: i386
Internal build version: 4.20.2F-7151045.4202F
Internal build ID: 774e0298-8f44-4c84-b62e-b7c5bce6e524
Uptime: 1 week, 1 day, 9 hours and 44 minutes
Total memory: 3956536 kB
Free memory: 2662344 kB
BTW, nice switches. Planning to use these in an S2D build with some dual port Connectx-4's. Anyone tried these in that type of config yet?