Sorry if came to the wrong place - couldn't find more suitable part of the forum to ask for help and advise.
Use AS-606T for ~2 years.
Only 2 HDDs are installed 2x4TB Seagate ST4000VN00 at JBOD mode.
ADM version - can't remember, seems to be the latest one. Updated it a week or two ago.
Today naitive UPNP server app was down all day.
When came home and entered web-inteface - it's icon was a blank white square and APP section was hanging on opening.
Although Storage section opened and didn't show any troubles with disks.
Made a soft reeboot via reboot button in the menu, and than it died...
No it always hangs on "BOOTING-STORAGE, PLEASE WAIT". Web interface is not available at this moment.
Any ideas waht could be the problem?

If I remove both HDDs - NAS loads normaly and reports that no HDDs are available.
Web-inteface can't initialize without any HDD installed.
Need advise on JBOD recovery.
What I SHOULD NOT do - not to harm data on JBOD HDDs?
Can I connect them both to my desktop (MB - ASUS P8P67 Deluxe) without a risk of data loss? RAID mode is active on desktop as there's a "Mirror" running on in it.
Will motherboard in desktop recognize JBOD RAID from ASUSTOR?
Or will I see them as two HDDs with readable data, if motherboard will NOT recognize them as a sigle JBOD array.
Or will I see the data on at least one of the HDDs if the other one is broken?
Will be greatfull for any help.
Thanks in advance!