Readynas RNDP 6000 with OS6 with crashed disk wont boot anymore, how to recover?

Hi,

I have a readynas RNDP6000 / ReadyNas Pro 6 with 6 disks.

A while ago I use the mothod found on this forum to upgrade it to OS6, worked like a charm. 

Now I have a disk that crashed and the system shut itself off to protect the raid array.

I put in a new disk and tried starting it up again.

The thing is, it wont boot anymore, the screen just says readynas, and nothing happens. Not even if you keep it on for hours. 

I also tried to boot the recovery menu (Holding the reset button on the back with a paperclip and start the device). But it wont come up.

Is there a different way to get to the boot menu beacouse its OS6 now (I only needed the boot menu before with the old OS, so I use the same method but am not sure if thats still the same with OS6).

Or shall I try to boot from a USB stick with recovery software, of so, wich recovery software do I need? the original Radiator 4.2 Recovery tool:| https://kb.netgear.com/30267/RAIDiator-4-2-USB-Recovery-Tool

Or one for OS6, and if so what is the one to use? Beacouse I can find a lot for specific types of nas systems, but of course not the one for RNDP6000 as it does not officially support OS6.

Please help as I really like to keep using my readynas.

PS, if the disks will get formatted its not a biggy, I have all my data still on my computer, and use the Readnas as backup system.