NanoBSD 6.2 Stable fails to mount filesystem on MikroTik RouterBOARD 230

[Phill Hocking]

Greetings. I am having issues with my NanoBSD images failing to boot 
that seemed to start in 6.1.

RTC BIOS diagnostic error 20<config_unit>

Timecounters tick every 1.000 msec

ad0: 488MB <SanDisk SDCFB-512 HDX 3.15> at ata0-masstray irq7

ad0: TIMEOUT - READ_DMA retrying (1 retry left) LBA=0
ad0: TIMEOUT - READ_DMA retrying (0 retries left) LBA=0
ad0: FAILURE - READ_DMA timed out LBA=0
ad0: TIMEOUT - READ_DMA retrying (1 retry left) LBA=0
ad0: TIMEOUT - READ_DMA retrying (0 retries left) LBA=0
ad0: FAILURE - READ_DMA timed out LBA=0
ad0: TIMEOUT - READ_DMA retrying (1 retry left) LBA=1
ad0: TIMEOUT - READ_DMA retrying (0 retries left) LBA=1
ad0: FAILURE - READ_DMA timed out LBA=1
ad0: TIMEOUT - READ_DMA retrying (1 retry left) LBA=0
ad0: TIMEOUT - READ_DMA retrying (0 retries left) LBA=0
ad0: FAILURE - READ_DMA timed out LBA=0
Trying to mount root from ufs:/dev/ad0s1a

I've tried several different flash carts, and my old 5x images work, so 
what should I do?

Phill Hocking