Edgerouter ER-X SFP - Bootloader Update within OpenWrt


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!

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Yes, you can write back with mtd as well.

The boot loader is what boots the OS, it's the 1st code that gets loaded.
If you break it, you've got a nice paper weight on your hands.

I'm not saying it's impossible, I've done it, on other devices. But if you make an
error, it's a dead device after the next reboot.

if you want to play it safe, upgrade the u-boot using the Ubiquiti firmware, then
go back to openwrt again.

Thank you very much for your feedback and assessment! Finally I went down the safe road and went back to stock, updated the bootloader and went back to Openwrt again. This was successful.

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