Hi there. Just to report (little) progress. I've made build6c with hot-fix for ETH_CFG register init (0x0000000), but it doesn't solve problem yet. I next steps will try to put quick and dirty fix for RST_RESET (clear ethernet switch reset bits) and GMAC0_MAC_CFG2 (set magic 0x01 on b9.8 as per documentation). If this won't fly we need to find a way to make ag71xx as loadable module to enable dynamic register changes and re-probing the module, while making separate builds for any register modification won't be convenient.
Q: How to make build where ag71xx driver is loadable module?