From QNAPedia

Regarding how to update the firmware manually via command line, you will have to upload the firmware image (e.g. TS-209_2.1.2_build1031.img) to a shared folder in the NAS (e.g. Public) first, and then execute several commands with SSH/Telnet.

If the firmware file is a zip file, then wherever you have copied it to on the server, firstly unzip it:

# unzip TS-410_3.5.2_Build1126.zip

You will get some minimal output with the above command:

Archive: TS-410_3.5.2_Build1126.zip
inflating: TS-410_3.5.2_Build1126.img

[Two important checks]

(1) Please make sure there is /mnt/HDA_ROOT/update folder.

If it does not exist, create it using

# mkdir /mnt/HDA_ROOT/update

(2) Confirm no /mnt/update file or folder.

If it exists, you need to delete it using:

# rm -rf /mnt/update

if you get a message saying:

“rm: unable to remove ‘/mnt/update’: Device or resource busy”, unmount the folder and try the rm line above again. To unmount use:

# umount /mnt/update

After the above two checks, execute the commands below to perform the update.

1. Copy the image file to the normal update location:

   # mv /share/Public/TS-209_2.1.2_build1031.img /mnt/HDA_ROOT/update/

2. Create a link to the /mnt/update location:

   # ln -sf /mnt/HDA_ROOT/update /mnt/update

3. Run the update script:

   # /etc/init.d/update.sh /mnt/HDA_ROOT/update/TS-209_2.1.2_build1031.img

Note while the update script runs, you will get some output feedback in the terminal, similar to the following. This particular update was conducted on a TS-410, with update package as shown, TS-410_3.5.2_Build1126.im, so here, as with any update, the various commands listed above which reference a particular update image would change with whichever update image you need to use:

[/] # /etc/init.d/update.sh /mnt/HDA_ROOT/update/TS-410_3.5.2_Build1126.img 
cksum=1727365263
Using 120-bit encryption - (QNAPNASVERSION4)
len=1048576
model name = TS-410
version = 3.5.2
16+0 records in
16+0 records out
3.5.2OLD MODEL NAME = TS-410
Allow upgrade
boot/
config/
fw_info
initrd.boot
initrd.boot.cksum
qpkg.tar
qpkg.tar.cksum
rootfs2.img
rootfs2.img.cksum
rootfs_ext.tgz
rootfs_ext.tgz.cksum
uImage
uImage.cksum
update/
update_check
update_img.sh
tune2fs 1.41.4 (27-Jan-2009)
Setting maximal mount count to -1
Setting interval between checks to 0 seconds
Update image using HDD ...
Update Kernel ...
4030+1 records in
4030+1 records out
Update Basic RootFS ...
17353+1 records in
17353+1 records out
Update Basic RootFS2 ...
6144+0 records in
6144+0 records out
1+0 records in
1+0 records out
Update Finished.
set cksum [1727365263]
[/] #

Then reboot the system after manually updating the firmware:

# reboot