backup system image from beaglebone black

Hi, I’m working on optimization beaglebone-black system cause it’s too large for us. And after reduce the unnecessary things from the original system, how can I backup this system into a image file and reflash to a new board?
The system image I used is AM3358 Debian 10.3 2020-04-06 4GB eMMC IoT Flasher, what I want to get is just the same img file like it and can auto flash into emmc
Thanks

see:
https://forum.beagleboard.org/t/create-a-full-image-to-redeploy/34628

Summary:
sudo dd if=/dev/mmcblk1 bs=1M of=<my_image> bs=1M status=progress
should work in most cases, otherwise use the beagle_flasher tool.

Note: if you want the resulting image to be a ‘flasher’ image, I believe you’ll need to mount the image then edit it’s uEnv.txt file.

thanks, I’ll try

from my point of view, edit uEnv.txt file is to uncomment this line, is it right?

##enable Generic eMMC Flasher:
#cmdline=init=/opt/scripts/tools/eMMC/init-eMMC-flasher-v3.sh

Hi, I met another question when I try backup system from emmc to SDcard. When insert SDcard and boot the board, it can only boot from SDcard rather than emmc and I did not push the usd boot key at all.
Do you know how did this happen?