u-boot v2022.01 and Arria-10 socdk not booting

I am working on an Enclustra mercury board and had some issues with booting, which stopped after (successful) FPGA configuration. (Console: FPGA: Enter user mode is the last line printed)

Since we also have an Arria10 socdk available, I decided to try that one. For the sockdk I have a working sdcard, which also includes a FitImage containing a peripheral and core rbf. I tried the card (boots) replaced the bootloader with a vanilla built socfpga_arria10_defconfig and booting seems to stop at a similar point. Last console message: "early release succeeded" and then it stops.

Am I overlooking something, or are there issues with mainline u-boot and arria10 ?

Any suggestions where to look ?