GS1900-48HP completely unresponsive after firmware 2.90 update – No port LEDs, no link

Corazon008

Hello,

I have a Zyxel GS1900-48HP switch. After updating the firmware to version 2.90(ABTQ.1)C0, the switch became completely unresponsive:

The Power LED is solid green, but all port LEDs are off.

Fans are running normally.

No Ethernet port shows a link; connecting a PC directly shows "cable disconnected" on the network card.

I tried a long reset (~20 seconds), but the issue persists.

I do not have a physical console port.


Before the firmware update, the switch was working perfectly.

Given that there is no network access and no port LEDs are active, I would like to know:

1. Is there any official Zyxel procedure to recover or reflash the switch in this state?


2. Can this be done even if the switch was purchased second-hand, or is there a limitation?


3. If recovery is possible, what are the exact steps to restore the switch without a console?



Thank you very much for your guidance.

Best regards,

Zyxel_Melen

Hi @Corazon008

According to your update, it seems like this switch encountered an issue related to the PoE. We have other cases where the switch's PoE has a problem, which causes booting to take a long time since the switch is running self-checking.

You can reference this post to check if this device is still under warranty.

Zyxel Support Portal [RMA] - Claiming Warranty Service for a Zyxel Product? – Zyxel Support Campus EMEA

Zyxel_Melen

Hi @Corazon008

May I know the status of the SYS LED? If it is blinking, could you help find a 4-pin console to get the booting message? Here is the location of the 4-pin console.

And here is the info of how to connect the 4-pin console:

How to use the 4 pin console to connect to Zyxel switch? — Zyxel Community

Thanks.

Corazon008

Hello, thank you for your prompt reply.

The SYS LED was turned off only the PWR was on.

But, hopefully, the switch is working again.

What I did ? Nothing 😅. After a long time unplugged (a whole night) when I plugged it back in the morning every LED was working and the ports also.

Have to mention that it's the third time that it "crash" and had to wait a long time. I couldn't find a pattern but previously it happened suddenly and yesterday it was after the update (maybe pure coincidence).

Zyxel_Melen

Hi @Corazon008

According to your update, it seems like this switch encountered an issue related to the PoE. We have other cases where the switch's PoE has a problem, which causes booting to take a long time since the switch is running self-checking.

You can reference this post to check if this device is still under warranty.

Zyxel Support Portal [RMA] - Claiming Warranty Service for a Zyxel Product? – Zyxel Support Campus EMEA