did you first flash the newer bootloader, then reset, *then* flash 8090mc? It will work fine if you do so (as the guide says)I just got ICX 7250. Following fohdeesha's guide works perfectly except the SPR08090mc.bin from download page can NOT be flashed to primary. Downloaded 8080f and works fine. In case anyone having the same issue.
#IP of your TFTP server: setenv serverip 192.168.1.8 setenv image_name ICX7xxx/SPR08090mc.bin setenv uboot ICX7xxx/spz10118.bin
#IP of your TFTP server: setenv serverip 192.168.1.8 setenv image_name ICX7xxx/SPR08080f.bin setenv uboot ICX7xxx/spz10114.bin