Techman

The parts you mentioned are all that's needed. I believe that the enclosure for the Zmatter board is currently out of stock.
Instead of buying the cable kit you might want to buy a USB PLM, which is currently in stock at Insteon, either way is workable.

I rebooted after the first time it happened. I just tried a package update and reboot, so I'll see what happens going forward.
The last time it happened it triggered my siren program at 3:00 am
UPDATE:    I traced the problem back to an 8 button KPL. The link tables were mismatched/corrupted. I did a factory reset and restore which seems to have fixed the problem. 
 

Unplug you PLM, wait about 10 seconds, then plug it back in. Is the green led on the PLM lit?
In the admin console, click on TOOLS, DIAGNOSTICS, PLM STATUS, does it show the PLM as connected?

Try removing power from the eisy for a few minutes. 
Clear your java cache including all installed applications, then download the IoX Launcher from here: https://isy.universal-devices.com/start.jnlp
After it powers up, press the front button ONCE, then wait about 10 minutes before you try to access the eisy.
 

It looks like you have your Rx and Tx connections reversed.  Also make sure that Insteon is enabled in your configuration screen.
Let me know if that resolves your issue

Your admin console and ISY firmware must always match.
You need to clear your Java cache, Including checking the box "all applications and applets", then download the IoX Launcher from this link:
        https://isy.universal-devices.com/start.jnlp
This will install the IoX Launcher and will automatically match your existing ISY firmware.
Note: the most current ISY firmware is 5.3.4, you should upgrade as it contains bug fixes.
 

There are two versions of the firmware, one for the PLM and one if you're not using a PLM. The reason it boots up in safe mode is because it's looking for the PLM.
You need to Install the Z-wave only version of the firmware.
Download firmware
  -  ISY 994i Series including Z-Wave support
  -  ISY 994i ZW, Z, or ZS Series (Z-Wave/Zigbee and/or if you do NOT have a PLM)

You need to first update your ISY to the latest firmware, 5.3.4. Once you restore the backup up on the eisy power cycle the eisy.
Prior to restoring the backup on your eisy you need to verify all your programs and scenes as the update from 4.9.0 to 5.3.4 requires some user intervention. Be sure to first read the firmware release notes.

If you have the 2413S PLM then you need the USB to Serial conversion cables
Serial PLM Kitfds - Universal Devices (universal-devices.com)
 
 

@Javi
I finally got it working. The esiy wifi was connecting to my guest network which blocked it from my main network, which is why it didn't show up. The wired connection was properly connecting to my main network.
Javi, thank you for all your help. It's much appreciated.
 

You can use any 12V 2A power supply. You can also purchase from UD:
https://www.universal-devices.com/product/12v-1a-power-supply/

Here it is.
 
 

The ISY994 supports a 32gb SD card. I'm currently using one as are many other forum members.
The following is from the link you provided.
"The ISY994i takes a MicroSD card. The max size is 32GB. Please look for a card with the newer A1 rating (A2 also works, but will fallback to A1 because the ISY994 does not provide hardware support required for A2). All other process steps below remain the same.]"

Some things to try:
     Check your ethernet cable.
     Check the ISY power supply voltage.
     Reboot the ISY
Do you have a PLM plugged into the ISY?
It's possible that the SD card is not seated properly or is defective
 

@DirtRoad
Try removing power from the PLM and the ISY, then power up the PLM, wait about 15 seconds then power up the ISY
If your able to access the ISY via the admin console on your LAN then the router is not the issue.