DL4100 could not boot after OS5 update

No message on the display.
It will auto reboot after a few minutes and repeat this loop.
Router says there is no wired device attached.

Right after the OS upgrade, it worked a while. Then it goes to standby mode and I could not connect to it. Manually reboot it and it is dead.

How to flash the old firmware?

You can’t rollback. I would suggest a soft reset. If the 4-second one doesn’t work, go for the other one


“can’t” is a strong word.

However. . . I have a suspicion that something was done to “make it harder” in the last two releases of the OS5 firmware.


I did both, but no help.

Well. . . true. . . .

. . .but standard unbricking procedures should work for the Single bay myclouds. The newer units. . .have had people perform rollbacks using “unapproved methods”. A search will reveal a few threads.

So there are two options now.
One is to flash the new or old firmware using another method to bring DL4100 alive, but I did not find anyone done it before, so I have no idea how to do it. It seems that WD did not implement a rescue method.

I also plan to buy a Synology NAS like DS920+. Can I just move the disks to Synology and recognized them? If not, how to recover the data from them (raid5)?

I have needed to pull power plug for 30 sec after a firmware update to get unit woking.

then after power restore system finally booted correctly.

  1. try a re-do of the firmware and note there may be a series of firmware versions to install
    (I may be thinking of os3 which needed to be latest before jump to os5 ?)

I kept it unplugged for a day and powered it on, but the symptom is the same. Since it does not boot to the system, so I need another way to flash the firmware, which is not available.

At this moment, it is quite dead, on the second night of the OS5 update.

Sorry, I didn’t read the whole thing, but take a look at this

Synology formats each disk with DSM so its not going to read WD disks, I moved from a WD to Synology and had to reload data from a backup. If you can’t power up your device, I’ve read (but not tested) that you can connect all disks in the raid to a PC and mount your volume there, easier in linux than windows. There are many youtube videos to that effect and I hope it works for you.

DS920+ personally makes me uncomfortable with one of the RAM slots welded, a minor failure there outside warranty may tank the device. Unless you use transcoding, 1621/1821 may be a solid choice at a higher pricepoint though cheaper per bay and come with better AMD processors, ECC RAM, shielded case and internal PSU, a much better value proposition overall. All Synology units have the same DSM software which is generations ahead of WD.