I happen to have the 7500 with 604e/166 board. I tried booting
using 1.4 boot floppy, successfully booted.
I used input(kbd) output(/chaos/control). I saw 
'RESETing to change Configuration !'  messages just after typed
> boot fd:0
also heard another sound for power on, so I thoght something
wrong happened but it was the way 7500 boots from floppy.

  I got following line among the boot sequence,
mc0 at obio0 offset 0x11000: irq 14,2,3: address 08:00:07:aa:bb:cc
I got network i/f configured by typing 
ifconfig mc0 (ip_address)
And ping was OK to the machine on the same segment.
(Those are the only things I have tried today.)
---
(Makoto Fujiwara)