TFTP Problems, trying to de-brick xiaomi mi router 3g

[BassXX]

Hey there, while trying to install Open WRT I bricked my router somehow.

The Kernel panics and reboots.

I am following this instruction to debrick.

I am running a tftp server on Windows with Tftpd64 (I verified with an Ubuntu VM that the server is working correctly)

When selecting option2 in u-boot I get this output:

You choosed 2
                                                                              0


2: System Load Linux Kernel then write to Flash via TFTP.
 Warning!! Erase Linux in Flash then burn new one. Are you sure?(Y/N)
 Please Input new ones /or Ctrl-C to discard
        Input device IP (192.168.31.1) ==:192.168.31.1
        Input server IP (192.168.31.100) ==:192.168.31.100
        Input Linux Kernel filename () ==:kernel0.bin

 NetTxPacket = 0x8FFE4040

 KSEG1ADDR(NetTxPacket) = 0xAFFE4040

 NetLoop,call eth_halt !

 NetLoop,call eth_init !
Trying Eth0 (10/100-M)

 Waitting for RX_DMA_BUSY status Start... done


 ETH_STATE_ACTIVE!!
TFTP from server 192.168.31.100; our IP address is 192.168.31.1
Filename 'kernel0.bin'.

 TIMEOUT_COUNT=10,Load address: 0x80100000
Loading: checksum bad
checksum bad
Got ARP REPLY, set server/gtwy eth addr (f8:0d:ac:23:3b:b5)
Got it
T T T

why does it say checksum bad? is there a bigger problem?

Out of curiosity I sniffed in wireshark: I can see tftp read requests, but the server seems to simply never reply. I also checked firewall rules and it should be ok.

what else could I look into?

Thanks in advance.

[frollic]

what does the tftpd64 log say ?

[Lucky1]

not say it's your problem but
for tftp on windows I have used "SolarWinds-TFTP-Server"
works well with easy to see whats going on

[BassXX]

Nothing there is no log there.

When tftp´ing from Ubuntu, it creates logs. But there are no logs when the router tries to tftp

@Lucky1 Ok will try with that. However, I already tried like 3 different Tftp programms like tftpd64, pumpkin, etc. None worked, always the same result

[frollic]

and you're sure the tftpd64 default interface (NIC) doesn't get reset back to 127.0.0.1 during the router (re)boot ?

[BassXX]

Yeah I noticed, it does reset after a few minutes to 127.0.0.1...

I thought I can prevent that by setting the setting "Bind Server" to 192.168.31.100 - did not help either

[Lucky1]

other then windows firewall witch you seem to have already checked
I fined just disable it white testing quick and dirty but works

[frollic]

you need to put some kind of dumb network switch between the PC and the router, then tftpd64 won't notice the port dip on the router side.

[BassXX]

@Lucky1 Well problem is that it is a managed work PC, I have local admin rights, but firewall is managed by policy so I can add rules but not completely disable it.

My private PC all do not have LAN ports anymore... I also have a RPi laying around here, so if it is really the Firewall I can try with that. But I kinda doubt it, since it works flawlessly with an Ubuntu VM

@frolic What kind of network switch? I have none here, is it obligatory or is there a way to do this without having to buy a switch?

Thanks!

[frollic]

@BassXX

What kind of network switch?

anything with at least two ethernet ports, since you're using static IP, it only needs to be able to move the packets.

@BassXX

is it obligatory or is there a way to do this without having to buy a switch?

it's recommended, but I've always managed without one ...

[BassXX]

So what would you suggest to try, before buying a switch?

Regards

[frollic]

you need to figure out why the 3g isn't requesting the file.

I'd start by testing all ethernet ports.

[BassXX]

I eventually gave up on Windows, took a RPi and it worked like a charm!

Now I will reinstall Open WRT, hopefully without bricking the Router again

Thank you!

[frollic]

congrats!

interesting, never ever had any issues with win/tftpd64, but then again, I seldom flash devices using that combo.