ReadyNAS ultra 4 stuck on booting

Hello everyone,

I have since a long time my ReadyNAS ultra 4 running on 4x3TB HDD (lost my account with the death of readynas.com).

My NAS, during the first years was a little bit tweaked (outside add-ons installation) :

-2GB RAM

-midnight commander installed to manage external file transfer, even when logged off (Ajaxplorer also did that, but there wasn't any feedback, and remote SFTP was somewhat buggy).

-chron job to manage several foscam IP cams, with continuous recording and then deleting all the videos without any movement

It worked like a charm until now, and of course, i forgot to heed the best warning out there : "when it's working, don't touch anything".

I didn't really look at updates since ages, and obvioulsy, many things had to be updated :

- raidiator 4.2.31 to install :

- lastest version of some add-ons to install

- and, browsing the forums, i discovered my bios was 1.09 and the lastest was 1.10.

In order :

- 2 weeks ago, i installed raidiator 4.2.31 : worked perfectly

- 1 week ago, as i couldn't make ajaxplorer 5.0 working with the pydio app, i decided to try ajaxplorer 5.2 : the app is now bricked, reinstalling the 5.0 version doesn't work.

- the day after, i tried installing the 1.10 bios, without success (felt like the installation didn't begin, and the logs showed that i was still with the 1.09 bios)

And the real problem comes here :

- i installed the latest php add-on : worked

- i installed forkeddaapd add-on : installation worked

- i tried to reinstall the latest bios (1.10) : the installation launched and finished, without any prompt

- i thought it worked.

- rebooted the nas, and it started without a hitch, except that my admin password didn't work anymore, and neither the defaut netgear one. All my add-ons were working, as i could connect to their webpage, and they were running

- i made the big mistake : i tried rebooting the nas, to see if this password thing was just a bug.

Now the nas is stuck to the booting process (displayed in the front screen, i waited an entire night without any change). I tried many things :

- it doens't appear in raidar

- it doesn't get any ip

- it is unreachable

- os reinstall in boot menu launch the reinstallation, but then the booting message stays on

- i can't make usb recovery to work, it doesn't recognise any of the usb stick i tried.

- i don't want to try factory reset

- i tried to remove disk 1, exactly the same behavior

- i removed all disks : reboots to the classical error : no disk

- i haven't yet tested with a blank disk (still need to find one)

Then, i tried to probe with the telnet mode :

- as i first thought it is a bios problem (silly me, if it was, i don't think it would boot at all), i reapplied the bios add-on, located in opt/biosflash : didn't change anything

- looking at forums, it is possible my firmare got corrupted, and even the one in the flash memory : i would try to reapply with telnet the firmware, but i don't know where to start with it : i don't know where i can find the firmware in the nas (or can i mount the usbcard and find it ?), and don't know how to reapply it.

- i just realised i can try to manually delete the lastest addons, to see if it changes anything (maybe one addon got incompatible with my firmware), but would deleting the folder be enough ?

Am i missing anything ?

Thanks in advance