Update as I play with it. I used a USB Serial cable to grab from the RX and TX pins:
- Without an SD card in,it just prints RomBOOT to the log on repeat.
- With the SD card (and image) the board looks like it endlessly tries to boot
heres the snippet that prints on repeat
Starting kernel ...
Welcome to Debian GNU/Linux 9 (stretch)!
Backup mode enabled
AT91Bootstrap 3.8.13 (Sat Dec 28 17:03:37 MST 2019)
SDHC: fix in place for SAMA5D2 SoM VDDSDMMC over-consumption errata
SD/MMC: Image: Read file u-boot.bin to 0x23f00000
MMC: ADMA supported
SD: Card Capacity: High or Extended
SD: Specification Version 3.0X
SD/MMC: Done to load image
U-Boot 2019.07-dirty (Dec 28 2019 - 17:04:14 -0700)
CPU: SAMA5D27 1G bits DDR2 SDRAM
Crystal frequency: 24 MHz
CPU clock : 492 MHz
Master clock : 164 MHz
DRAM: 128 MiB
MMC: sdio-host@b0000000: 0
Loading Environment from FAT... *** Warning - bad CRC, using default environment
Net: No ethernet found.
Autoboot in 3 seconds
switch to partitions #0, OK
mmc0 is current device
SD/MMC found on device 0
473 bytes read in 10 ms (45.9 KiB/s)
Importing environment from mmc (uEnv.txt)...
Running default loadzimage ...
4393840 bytes read in 280 ms (15 MiB/s)
24592 bytes read in 23 ms (1 MiB/s)
Checking for overlays ...
Booting from mmc ...
## Flattened Device Tree blob at 21000000
Booting using the fdt blob at 0x21000000
Using Device Tree in place at 21000000, end 2100900f