Recover RB750Gr3 after a failed sysupgrade

Hi, I got a power outage during sysupgrade of my RB750Gr3 which was already running openwrt 18.06 and now the device is technically bricked. Is there any guide to recover this device using tftp since i already have uboot installed.

I believe those instructions are in the same location:

Unfortunately that only me shows how to tftp to install uboot. But after uboot is installed, the trick bellow wont work.

Connect your 750Gr3 Ethernet port 1 to the DHCP/TFTP server. Press and hold the reset button whilst powering it on. Keep pressing the reset button until the USR light goes out (it will flash a few times first, don't let go until it goes off completely.)

Then perhaps, you need an SPI flasher.

Not really. I plugged in a TTL serial and i can see the boot process, so uboot is still there. I just dont know how to stop the process to send the image using tftp. It shows press 9 to send image, but i press and nothing happens.


  • Have you tried CTRL+C?
  • It appears you're getting garbled text, have you set the serial setting properly?
  • Have you connected Ground?

Firstly, You'd better check the serial connection.

It will be safer to select [Load system code to SDRAM via TFTP], and send rb750gr3-initramfs-kernel.bin to the board using a tftp server.
If it works, an OpenWrt will run from RAM. Then you can use OpenWrt's sysupgrade to flash rb750gr3-squashfs-sysupgrade.bin.