Good news and bad news.
I was able to boot from your rootfs...once. After booting, I glanced at the device's screen, and it was at one of the configuration screens (date time?). I have not been past the original boot screen in some time.
I was able to run some of the commands you suggested. See the attached log.
However, when I rebooted, it wouldn't start again. I get these messages when I try to bootsd. I tried rebuilding the SD card from rootfs.tar.gz, with no luck.
Code:
Hit any key to stop autoboot: 0
eBR-1A #
eBR-1A # bootsd
Boot from SD
From 0x00080000 to 0x00280000
Target read size = 0x00200000
Booting image at 31000000
Bad Magic Number
eBR-1A # bootsd
Boot from SD
From 0x00080000 to 0x00280000
Target read size = 0x00200000
Booting image at 31000000
Bad Magic Number
I guess I'll need to use RandomInsano technique for rebuilding the kernel? Starting it now...