Found the problem with dosdcard.sh we need to do following.
Create a udev rule on build host
$ cat /etc/udev/rules.d/71-device-name.rules
# See - https://github.com/OE4T/tegra-demo-distro/blob/master/layers/meta-tegrademo/scripts/setup-udev-rules
# Jetson Nano
SUBSYSTEMS=="usb", ATTRS{idVendor}=="0955", ATTRS{idProduct}=="7523", MODE="0660", TAG+="uaccess"
sudo udevadm control --reload
Now please disconnect/reconnect your device
Then add your username to disk group. So you can avoid need for sudo
while running doflash or dosdcard scripts. Running under sudo can be quite dangerous if accidentally device chosen is wrong one ( least the data disk on workstation )
sudo usermod -a -G disk kraj
The install these packages
sudo pacman -S dtc gptfdisk
gptfdisk is providing sgdisk utility which is needed to create GPT tables on SD card.
In the end logout of the system and log back in so new group permissions are added to the user credentials.