You should read this (if you haven't already):
I performed the TFTP from within windows, using the TFTP software that I found on that page.
One trick is to keep a constant PING going while the M2 is re-booting.
Example: PING -t 192.168.1.20
During the re-boot, the PING TTL will change from 100 to 64.
You need to start the TFTP while it is still showing a TTL of 100.
Waiting until the TTL is 64 will end up in failure.
Beyond that, the only issue that I'm aware of is if you have a M2
that falls into the "XW" category.
If you have a "XW" you'll need
a different BIN file than the "XM" version M2.
You can see which version (XM/XW) you have by looking under the
SYSTEM tab of v5.6.2,
which will show you the current firmware loaded and more importantly whether it is
a XM or XW version.
I have performed this recovery many times using this method.
Hope this info helps!