Looks like there is no way that I can edit the original post. I'll post the update here.
For anyone experiencing the same issue, TLDR:
Call customer service at your earliest convenience. This is a hardware issue.
Power off the router, PRESSAND HOLD the reset button (with a pin) and power on the router
Keep the reset button pressed for ~10 seconds, maybe 20 or 30 seconds. Do note that, during this process, NONE of the indicators will blink or change color, though both are expected in a "normal" reset when your router is working fine
Release the reset button and cross your fingers. If you see the solid white power indicator, congrats!
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I'll summarize the details and info from the customer service here, if anyone is interested.
For the light indicators, since I have all LAN port connected w/ ethernet cable, "1, 2, 3, 4 and 5 all lit up. Then after a few seconds, all went off" is an indication that the booting process went wrong
I also noticed that, LAN port 1 and 2 is showing solid ember while 3, 4 and 5 are showing solid white before they went off. This simply means that LAN port 1 and 2 are connected with "lower speed" while 3, 4 and 5 are connected with "higher speed". Nothing wrong with this.
The "forever" solid ember power light simply means that, the router is stuck during the boot process, most possibly due to the firmware issue
Network indicator (the one right next to the power indicator) will not show up for sure, since that is the next step after boot process
When connecting the router to a laptop via LAN port, it is giving me "cable unplugged" error, which is another indication of firmware issue
At this point, Reset button won't respond if you leave the router on. But if you turn the router off, hold the reset and turn it on, it might work, according to the representative. We are both aware that this is not documented anywhere, since this is not expected for most of the cases
I remember the firmware version is ending with 88, which is the latest as of now (Jun 11, 2020). According to the representative, there is a known issue that this firmware may cause the failure of booting for specific routers
Still, according to the representative, as a user, we are supposed to upgrade the firmware as soon as there is one. Since firmware upgrade usually contains security updates that fixes existing/known vulnerabilities on your router
If the above won't fix your issue, call customer service at your earliest convenience
