An Oland card in the pciex16 slot and a Radon HD6570 in a pci slot using a a pci topciex16 adapter .
Workbench starts displaying then the computer freezes at about the display of the Amidock items.
I have tried with WBstartup disabled and get the freeze.
I don't need the second Graphics card under AmigaOS 4.1 but for Linux .
Have been able to boot AmigaOS 4.1 update 1 ok with a pci Radeon 9250 as the second card in the pci slot.
Have sent some debug output to Hans de Ruiter and he says that the Radeon HD driver is loaded for only one graphics card.
I don't see anything wrong there. In fact, your log shows that the driver is only loaded for one graphics card. I see no debug entries for a second one, which means that the driver isn't even touching the second one.
Given that dual Radeon HD cards works on other systems, it's highly likely that the problem lies elsewhere. Perhaps UBoot doesn't initialise two PCIe graphics cards properly, resulting in an address conflict (e.g., both using the same IRQ or something).