NAS325v2: Proper procedure to update firmware via USB stick?

asittler

Issue: After an unattended upgrade to 4.81 (most likely, as I didn't pay attention) via the web UI, I can't hookup to the volumes via smb anymore.
The system LED is constantly blinking green.

The NAS shows up on my router, DLNA seems to work (as I can see videos/pictures on the TV),
but I can't connect via smb or telnet as I used to.

I therefore decided to manually downgrade the firmware again.
I downloaded various ones for my model from firmware ftp://ftp2.zyxel.com/, but it is unclear
- what the directory structure on the USB stick should look like
- which USB port to use on the NAS
I tried with 
- unpacking zip in root dir and trying all three USB ports.
I never saw an orange blinking of the system LED, so something is not going as expected.

Last resort would be to reset of course, but I want to avoid reconfiguration if possible.
Anyone any idea?
TIA,
Andreas

#NAS_Jan_2019

asittler

Update: I now have both nc and telnet access to the device on port 23 with my admin account.
The device apparently runs 'Linux 2.6.31.8 #2 Fri Jun 23 11:03:47 CST 2017 armv5tel GNU/Linux'
Any idea how to proceed from here?
I found this link http://zyxel.nas-central.org/wiki/Boot_process_(300_series) 
I also found a few logs in /i-data/md0/.system/ 
Still investigating...
Any hint appreciated...
Probably there is a way to revert from the cmdline without any USB stick?

Clay_JF2019

You sure you need to revert now that you have access to modify files? 

It would seem like the problem is more likely misconfiguration of new firmware in scripts and .conf files rather than upgrade firmware modules are actually written faulty. Coders sometimes worry more about fresh config rather than successfully importing old config files after upgrades.

Checking init.d start up scripts might yield some features that do not start because the line is commented out by configuration switches. Might be some script variables.  Surely someone here can send or advise you on what the start up scripts should look like to get the missing features up.

Mijzelf

An answer to your orginal question:

I have collected some recovery sticks here . Unzip the right one to an usbstick, put it in a back port, and reboot the NAS.

I don't know if that is the most meaningful way to solve your problem. Neither if it will solve it.

asittler

@Clay_JF2019 Thanks for the response.
Your suggestion is clearly the better way, but, apart from further investigation, requires root access, no?

asittler

For the interested:
Thanks to https://homeforum.zyxel.com/discussion/649/root-account/p1 I know the password of root (which is identical to admin).
I then ran
/etc/init.d/samba.sh stop
/etc/init.d/samba.sh start
and samba is working again, which was my main goal.
I'll investigate further and update this thread once I have all things auto-working again.