OWNLOAD OPENWRT FIRMWARE
Firmware for Mikrotik

DOWNLOAD TINY PXE SERVER
Link to PXE Server

FLASH THE ROUTER USING THE TOOTHPICK METHOD
Start and configure the PXE Server (192.168.1.10/24, * -initramfs-kernel.bin). Turn off the Mikroitk power, hold down reset, turn on the power and release the toothpick after 20 seconds.

UPGRADE FIRMWARE TO FULL VERSION
After booting the router via PXE, go to the router and update the firmware to the full version (* -squashfs-sysupgrade.bin)