If you use recent OpenWrt (ie. snapshot or 22.03-rcX) /etc/fw_env.config will be generated automatically. I’d highly recommend to just use recent OpenWrt.
Thanks i tried latest snapshot it worked but now i cannot save custom env on u-boot console using saveenv command it returned me that “mmc is not present”. When i plugged sd card into mmc slot it successfully saved env on eMMC not mmc.
Yes, that’s a known problem because boot device detection doesn’t always work reliable and maybe we will have to use separately builds for U-Boot depending on the boot device (just like for the R64 and upcoming R3 board) instead of relying in what the preloader leaves behind in memory in order to identify what it was booted from. Patches welcome 
Yeah , I will try to build u-boot from source for R2 i have limited knowledge about building from source and apply . If you have any wiki about that it will be appreciated. Then i can patch this problem
Is there any way to sysupgrade to this image? No 21.02.x sysupgrade seems to understand the image tree block sysupgrades in 22+
You can try with the sdcard image, 21.02.x and earlier used full-disk image as sysupgrade format, so that could work. However, you can’t keep your existing config.