Hi Paul,
Thank you for engaging with us on this. As Graham says, I have the CTE CPLD display and use UTFT_GHL to drive it. I have tried SD and it does indeed work OK with Ethernet. That's what I was originally using but it still leaves the issue of getting the display flash to work as well.
It's still not clear to me whether the issue is in the Ethernet library or in SdFat/UTFT_GHL. I suppose Graham could try using the SD SPI interface code instead.
Regards,
John.