Trying to upgrade to 2017.07-2023.04 U-Boot (no replies)

After many years (back in 2017 I guess), I wanted to assign some new job to my Pogoplug V4, however I lost the USB pen drive where I created the original rootfs. After connecting the Pogov4 through a usb-serial console from a Ubuntu desktop, I get this:

Pogov4> reset
resetting ...

U-Boot 2017.07-tld-1 (Sep 05 2017 - 00:34:01 -0700)
Pogoplug V4

SoC:   Kirkwood 88F6192_A1
DRAM:  128 MiB
WARNING: Caches not enabled
NAND:  128 MiB
MMC:   MVEBU_MMC: 0
In:    serial
Out:   serial
Err:   serial
Net:   egiga0
No link on egiga0
ping failed; host 192.168.0.100 is not alive

I wonder do I need rootfs created before I can update the newer 2017.07-2023.04 U-Boot? If yes, which version of rootfs I need to create? Also these instructions doesn't make any sense from my Ubuntu desktop screen session to Pogoplug. Essentially I forgot what I did and how I did everything back then. I'm trying to follow these instructions found here: https://forum.doozan.com/read.php?3,12381

1. uBoot envs config should be defined as followed in your /etc/fw_env.config

cat /etc/fw_env.config
 # MTD device name	Device offset	Env. size	Flash sector size	Number of sectors 
/dev/mtd0 0xc0000 0x20000 0x20000

- And your mtd partitions should be:

cat /proc/mtd
dev: size erasesize name 
mtd0: 00100000 00020000 "u-boot" 
mtd1: 00400000 00020000 "uImage" 
mtd2: 02000000 00020000 "rootfs" 
mtd3: 0db00000 00020000 "data"

Question 2: I prefer not to use a USB stick or SD card for booting the PogoPlug. Is it possible use a 2.5 inch SSD mounted on top to handle the boot process. I think SSD would be more reliable?

Thanks again.