You can override any board option declared in manifest file using the next
format board_{OBJECT.PATH}, where {OBJECT.PATH} is an object path in
JSON manifest. Please navigate to “boards” folder of PlatfomIO development platforms
and open JSON file to list all available options.
For example, Manifest: Espressif ESP32 Dev Module:
[env:custom_board_options]
; Custom CPU Frequency
board_build.f_cpu = 160000000L
; Custom FLASH Frequency
board_build.f_flash = 80000000L
; Custom FLASH Mode
board_build.flash_mode = qio
; Custom linker script
board_build.ldscript = /path/to/ldscript.ld
; Custom maximum program size
board_upload.maximum_size = 1310720