CCR2116-12G-4S+ continuously rebooting before login – need recovery guidance

RouterOS
1

Hi MikroTik Team,

We have two MikroTik CCR2116-12G-4S+ routers that suddenly started continuously rebooting. Both routers were working normally earlier, but now they keep restarting in a reboot loop.

We connected to the routers using the serial console (PuTTY), but before we can enter the login credentials, the router reboots again.

Troubleshooting Performed

  • Verified the power supply.
  • Disconnected all network cables.
  • Connected only the serial console cable.
  • Tried accessing the router through the serial console.
  • The reboot loop continues on both routers.

Information/Logs

We have attached the serial console output/logs and screenshots showing the reboot process.

Could you please help us determine:

  1. Does this indicate RouterOS corruption, bootloader/software failure, or a hardware issue?
  2. What could cause continuous rebooting on a CCR2116?
  3. Is there any way to access RouterBOOT/Netinstall recovery when the device reboots before login?
  4. What is the recommended recovery procedure without losing the existing configuration?
  5. Is there any specific diagnostic command or key combination we should use from the serial console?

Any suggestions or troubleshooting steps would be appreciated.

Thank you.

Screenshot from 2026-09-06 01-17-05
Screenshot from 2026-09-06 01-17-051834×587 145 KB

2

Netinstall - RouterOS - MikroTik Documentation - you can use the hardware reset to force it into netinstall. I would try that as a first call. Based on your screenshot, I dont think you are going to be able to recover that.

3

Have you tried also the "other" bootloader?
JFYI:

4

Sure, we will try the hardware reset method first to force the MikroTik router into Netinstall mode and proceed with the recovery. We will update you with the results.

5

The screenshot prints a stream of non-recoverable ECC (Error-Correcting Code) memory events.

[edit]
A fact that two routers have suddenly developed the same hardware issue is a mystery.

Is there is more to this story?
an attempt to replace RAM on these devices?

6

Can be the hack... No one ask RouterOS version or active services before both start to not work...

7

If I am reading the screenshot correctly these are hardware errors in pre-boot environment.

8

At the same time on 2 devices?
Something that have changed memory frequencies on settings?...

9

Exactly, and this is the smoking gun. Two devices can't suddenly fail in the same way.

In other words, either we are not being told the whole truth, or ... these devices were hacked. For example bootloaders were compromised. Let's say a remote hacker takes control of the devices, sets own update mirrors, sets the firmware upgrade to yes, and initiates RouterOS + firmware upgrade.

10

One more thing: posted by a user who registered a mere 3 hours ago...

11

Well, people need to start somewhere ... :astonished_face:

12

Do you mean some 3rd party team of "security researchers" discover vulnerability and offers a fix to a vendor for a fee?
Say a vendor considers the price tag expensive, such practice unethical, or outright criminal, and refuses to cooperate. Then "security researchers" start flexing the muscle, and escalate ?

13

On a couple of my older CCR2116's, they show this stream of characters as the router's stage_2 loader is clearing RAM (memory repair). Newer models don't show the big long lines of asterisks.

What we be more interesting is to see if it gets to RouterBOOT.