Reflashing (when things go wrong) - Xiaomi Mini

I decided to downgrade from trunk to 15.05 RC2 (not all packages were available in trunk)
weird things happened trying to reinstall packages. I think the real culprit was that /etc/opkg.conf was still pointing to trunk.(i downgraded with 'keep configuration')

anyway, reflashing is easy:

cd /tmp
wget http://downloads.openwrt.org/chaos_calmer/15.05-rc2/ramips/mt7620/openwrt-15.05-rc2-ramips-mt7620-xiaomi-miwifi-mini-squashfs-sysupgrade.bin
sysupgrade -n -v
openwrt-15.05-rc2-ramips-mt7620-xiaomi-miwifi-mini-squashfs-sysupgrade.bin

done!

this zaps all config files so you'll have to telnet in via 192.168.1.1 (cfr firstboot)
but as a bonus the 5Ghz radio seems to be working now.
(turns out with RC2 it's recognized but the network fails to come up - logread mentions something that makes me think it's outside of my reach to fix)

However I did not get as much joy out of RC2 as out of trunk. Installing luci seemed okay, but as soon as i touched the network settings the xiami became unreachable.

! seems RC2 requires a hard power cycle when changing (some) network settings (especially the switch seems touchy )

only way out was the emergency/recovery/failsafe procedure:

unplug power
plug in the WAN
plug in power
randomly poke away at the reset button (the LED doesn't help)

after a couple of tries. you'll manage to telnet in and zap the config e.g.

mount_root
firstboot

and you'll be back to a fresh start.