Can't boot after upgrade from 2.2.4 to 2.3.1 (Stuck at updating configuration)

[mastablastaz]

Hi,

I upgraded my Soekris net5501-70 (4GB flash card, WLM200NX Atheros AR9220 wifi card) from 2.2.4 to latest 2.3.1 with the console:
Following tutorial https://doc.pfsense.org/index.php/Upgrading_via_Shell_(old)

/etc/rc.conf_mount_rw
fetch -o /root/firmware.tgz https://updates.pfsense.org/_updaters/latest-nanobsd-vga-4g.img.gz
/etc/rc.firmware pfSenseNanoBSDupgrade /root/firmware.tgz

During install I got below messages but the appliance still rebooted:
ath0: stuck beacon; resetting (bmiss count 4)
kern.geom.debugflags: 0 -> 16

Now when I try to boot I can see that my firmware is updated to latest version:

FreeBSD 10.3-RELEASE-p3 #1 3ef16fb(RELENG_2_3_1): Tue May 17 19:52:20 CDT 2016
Geode LX: Soekris net5501 comBIOS ver. 1.33 20070103 Copyright (C) 2000-2007
Welcome to pfSense 2.3.1-RELEASE on the 'nanobsd' platform…

However the boot sequence is getting stuck at "Updating configuration" step in what seems to be an infinite loop so I have to CTRL+C to get out of the loop.
Do you have any idea how can I debug or fix that?
I'm thinking that I need to retrieve my /conf/backup/config-*.xml and reinstall from scratch but I would like to prevent that...

I attached my boot sequence logs.

Thanks in advance :)
pfsense_boot_error.txt