1. check if your MAC speed mode is set fixed on 1000 mode .
if yes ->set to 10/100 mode or 100 mode.
2. cehck phy speed & duplex mode is get correct.
gega mac 1G mode setup is different from 10/100 ,most vendor's gega mac design is same ,
2 mode for speed one for 1000 only one for 10/100 !
if mac speed is set on 1000 ,the auto negotiation may be not working on 10/100 hub or any 10/100
network adapter!