[j-nsp] Backup u-boot image on SRX210?

[prd::S]

Hi, All.

A power outage occured when I was flashing the u-boot image on an
SRX210 via tftp.
Then there's no output on the serial console even after several resets.
I suspect that the primary u-boot image might be corrupted.

The questions are:
Does SRX210 has a backup u-boot image?
If so, how to boot from that image?

I would like to give it a try before the RMA process.

Thanks!

-PRD.S