Edgerouter ER-X SFP - Bootloader Update within OpenWrt

Hi,

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!

1 Like

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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