Failed to connect to ubus

[mwarning]

Hi, I try to flash my device in recovery mode and get this error.
How can I work around/debug/fix this issue?

root@(none):/tmp# sysupgrade -n lede-ramips-mt7620-wt3020-4M-squashfs-sysupgrade.bin 
killall: watchdog: no process killed
Commencing upgrade. All shell sessions will be closed now.
Failed to connect to ubus

[anon57995562]

See these steps @slh provided in this thread...

BT Home Hub 5A Recover LEDE v17.01.4

No, the USB port isn't usable for that task (you may be able to avoid flashing over the serial console, given that u-boot should still be fine to use tftpboot - are there better recovery methods for uboot-lantiq without needing a serial connection?). But given that you can enter failsafe mode, I really don't understand why softreset and/ or flashing from failsafe mode don't work for you. What happens if you go back to step 1. power off the router access failsafe mode execute the "firstboot" b…

Make sure you use lowercase y when answering the firstboot prompt.

[mwarning]

It worked after executing firstboot. - thanks