Recovery RB through Serial access (putty, hyperterminal...)

RouterOS General
1

Hi, Mikrotik routerboards has inside an e-jtag and serial port (3.3v, gnd, tx and rx)… As I understand this last (serial port) is used to recover MK boards (console mode) that can´t be recovered through netinstall…

First I´m trying with a working board to find the way… of course

How is the way to access to this mode? I tried several times but no luck.

I use an usb-rs232 adapter and tried too with CP2102 adapter (no luck too)…

I configure putty 115200, 8 1 N N in the respective COM port.
TX from serial to RX from RB
RX from serial to TX from RB
GND with GND RB
Power from PoE

Anyone tried to recover MK boards with this method??

Thanks!!

2

I tried it once with older RB711 and it didn’t work. Then I found somewhere (I think OpenWRT wiki) that the serial port works, but only from OS, bootloader doesn’t use it. I don’t know it for sure, maybe my board was just more dead than shining leds suggested (I didn’t manage to resurect it). And even if it is true, other models can be different.

3

At the very least you will probably want a TTL Serial adapter rather than the usual RS232 one you’d normally use, RS232 can signal with voltages from something like -15V to +15V whereas TTL will be 0-3 or 5v