Set up issues on F-423

[soepicithurts]

Trying to set up the nas offline. Connecting to an internet enabled network is not an option as the gateway is in another room. Nas is connected to an unmanaged switch. All documentation i've seen has pointed to this being possible, however:

Set up:
1x 256gb NVME drive installed properly
1x 4tb WDRed drive

Attached to
TP-link 5-port gigabit switch

from there, attached to PC

Assigned an IP and got to boot manager
boot manager fails to load
install via download

initialization
default option greyed out
choose custom
Select drives to install on
Install
both drives pass
select Nvme
Install 4.2.40 TOS Installation Package
Nas reboots
disappears from TOS PC/wont show up after inputting IP

Uninstall NVME drive, remove WDRed.
Assign Ip
Boot manager
install via download
initialization
install WDRed
default option greyed out
choose custom
Select drives to install on
Drive passes
Select WD Red
Install 5.1.24 TOS installation package
Nas reboots
disappears from TOS PC/wont show up after inputting IP.

again, directly connecting the nas to the internet is not an option.