Octopus

first, use make menuconfig to select these options

For BTT Octopus v1.1 (STM32F446):
Micro-controller Architecture: STM32
Processor model: STM32F446
Bootloader offset: 32KiB bootloader
Clock Reference: 12 MHz crystal
Communication interface: USB (on PA11/PA12)
If using CAN instead of USB:
Communication interface: CAN bus (on PD0/PD1)

then copy to firmware.bin on sd card

Flash method: make flash FLASH_DEVICE=/dev/serial/by-id/usb-Klipper_... via DFU or SD card copy of klipper.bin renamed to firmware.bin.