I’ve been able to update uboot env making the partition writable, removing the line

But stock firmware can write uboot env and partition is read only. I’ve seen in the files (i don’t know what are you using in stock firmware)

Branch openwrt-19.07.7

Branch openwrt-18.06-s1300

Branch openwrt-trunk

Is there any other way, more secure, to be able to update uboot env without making the partition writable?