I own a ER-X SFP and directly installed OpenWrt - works great so far.
Later I've read that a new version of the bootloader (uboot) provided by Ubiquiti enables a TFTP recovery without connecting to the serial port. Unfortunately Ubiquiti provides this update only included in a full firmware update: https://help.ui.com/hc/en-us/articles/360019289113-EdgeRouter-TFTP-Recovery
My question is: Is it possible to update the bootloader within OpenWrt? So far I was able to extract the bootloader file from the firmware update. And my thought was, as I can download the bootloader from its mtd partition (mtd0) via OpenWrt, why not write the updated file to mtd0 also via OpenWrt. As I have no experience with that, I would like to get an idea, if this should be possible or not, what could go wrong etc.?
Thank you for any feedback!