I'm looking for working sources of u-boot for M2 Ultra. I tried several u-boot's among others from uboot-sunxi or uboot-nisenbeck, recompiled them but none of them started at my M2 Ultra. Then after successfull compilation I wrote given uboot on SD card with dd command:
dd if=uboot-sun-8iw11p1.bin of=/dev/sdc bs=1024 seek=40
but after I powered the M2 ultra board - no messages appeared on serial console and only red led was on.
Any ideas where can I find the sources? Or maybe I'm doing something wrong?