After firmware 5.27.157 update, RAID configuration is gone and consequently no access to data

I lost access to my JBOD volume 1. These instructions didn’t help, but I assume it may be something different I need to type out

root@MyCloudEX2Ultra ~ # mdadm --assemble --run /dev/md1 /dev/sda2
/dev/sdb2;
mdadm: no recogniseable superblock on /dev/sda2
mdadm: /dev/sda2 has no superblock - assembly aborted
root@MyCloudEX2Ultra ~ # cat /proc/mdstat;
Personalities : [linear] [raid0] [raid1] [raid10] [raid6] [raid5] [raid4]
md0 : active raid1 sdb1[1] sda1[0]
2094080 blocks super 1.2 [2/2] [UU]
bitmap: 0/1 pages [0KB], 65536KB chunk