I'm no layer2 expert either. But as I understand it from what I have read, what basically happens on the HW level is; (100BaseTX)

some_timed_IRQ_handler(){
if (Autonegotiation_Enabled) autonegotiate;
else send_periodic_100BaseTX_link_pulse;
send_link_pulse
}

received_something_handler(){
if (received_autonegotiate) negotiate();
else if (received_100BaseTX_link_pulse) set_100BaseTX_link;
else if (received_link_pulse) set 10BaseT_link;


Now a 10BaseT chipset such as the empeg knows nothing about the 100BaseTX stuff, so is much simpler;

some_timed_IRQ_handler(){ send_link_pulse(); }

received_something_handler() { if (received_link_pulse) set_link; }

Now, I'm assuming that autonegotiate() actually involves sending some layer2 data and doing a full handshake.

So from this and what you posted earlier (getting link, later ping failing), the switch has already done what it is supposed to. Unless it has mysteriously forgotten and does it again the first time data is sent. I can't see how the empeg can foul this up - it _only_ knows about 10BaseT link pulses.

The other possibility is that the switch has a buffer problem (possibly in HW) whereby the first X bytes get lost.