Flash RCW to BANK1

Re/configure U-boot

Change Factory U-boot config target from ls1021atwr_sdcard to ls1021atwr_lpuart. If compiling U-boot outside of Factory, use ls1021atwr_lpuart as your config target.

Clean & rebuild U-boot.

The resulting binary will simply be named u-boot.bin in build_*/images/bootloader/.

Flash new RCW and U-boot

RCW: rcw_1000_dcu.bin

This file is located in the the rootfs, as well as the Factory working build directory at:

rfs/boot/SSR_PPN_20/rcw_1000_dcu.bin

To flash:
First, boot the board from VBANK0, SW3.5 must be OFF.

Flash RCW and U-boot as follows:

tftp 81000000 u-boot.bin
tftp 82000000 rcw_1000_dcu.bin

protect off all;erase 63f80000 63ffffff;cp.b 81000000 63f80000 80000
protect off all;erase 64000000 6401ffff;cp.b 82000000 64000000 100

Once that is done, on jumpers J19,J20 - short pins 1&2 to enable LPUART.
Change SW3.5 from OFF to ON, so that VBANK1 is booted.

Disconnect USB-TTY adapter, power off hardware; re-connect USB-TTY adapter, and re-open serial console, apply power.

Change bootargs

At this point, you can boot with HDMI by adding the following argument to your bootargs: hdmi res=600x480

Switch settings for SW2, and SW3:

SW2: 10001111
SW3: 01101001

Example bootargs:
console=ttyLP0,115200 ip=dhcp root=/dev/nfs rw hdmi res=600x480