ReadyNas Pro 6 Frontview 4.2.x page - blank buttons

Hi,

mdgm-ntgr helped me to recover a boot menu in my readynas pro 6, in this thread https://community.netgear.com/t5/Using-your-ReadyNAS/Cannot-access-boot-menu-on-ReadyNAS-Pro-6/m-p/1020621#M100235

and I thought that I could go from there by myself, but no.

Now, after an OS Reinstall, a Factory Reset (and almost a week without Internet connection at home), I'm stuck with a frontview 4.2.x web page with blank buttons 

RAIDar is like that :

I plan to recover an (unsupported) ReadyNAS OS 6 version on my Pro 6 (or, at least, a working 4.2.28), but I don't know how to handle this from that point (I can't flash firmware from the web GUI since it doesn't show any button).

I've tried several "OS Reinstall" from Boot Menu and "Factory Reset", with no luck.

I know that I can access my ReadyNAS through Telnet when I put the NAS in "Tech Support" mode (I've tried it and it works, I can browse the linux busybox filesystem), but I don't know what to do next.

If anybody could help me, I'll really appreciate it.

(Note that I put a totally blank - diskpart clean - Netgear supported single disk in the NAS 

Thank you in advance

Sebastien