My_platformIO set up for the BBB or BBAI...

[platformio]
src_dir      = Marlin
boards_dir   = buildroot/share/PlatformIO/boards
default_envs = stable
include_dir  = Marlin

...

[env:stable]
framework     = arduino
extra_scripts = ${common.extra_scripts}
build_flags   = ${common.build_flags}
lib_deps      = ${common.lib_deps}
monitor_speed = 250000
monitor_flags =
  --quiet
  --echo
  --eol
    LF
  --filter
    colorize
  --filter
    time

...

#
# NXP LPC176x ARM Cortex-M3
#
[common_LPC]
platform          = https://github.com/p3p/pio-nxplpc-arduino-lpc176x/archive/0.1.3.zip
platform_packages = framework-arduino-lpc176x@^0.2.5
board             = nxp_lpc1768
lib_ldf_mode      = off
lib_compat_mode   = strict
extra_scripts     = ${common.extra_scripts}
  Marlin/src/HAL/LPC1768/upload_extra_script.py
src_filter        = ${common.default_src_filter} +<src/HAL/LPC1768> +<src/HAL/shared/backtrace>
lib_deps          = ${common.lib_deps}
  Servo
custom_marlin.USES_LIQUIDCRYSTAL = LiquidCrystal@1.0.0
custom_marlin.NEOPIXEL_LED = Adafruit NeoPixel=https://github.com/p3p/Adafruit_NeoPixel/archive/1.5.0.zip
build_flags       = ${common.build_flags} -DU8G_HAL_LINKS -IMarlin/src/HAL/LPC1768/include -IMarlin/src/HAL/LPC1768/u8g
  # debug options for backtrace
  #-funwind-tables
  #-mpoke-function-name

#
# NXP LPC176x ARM Cortex-M3
#
[env:LPC1768]
platform  = ${common_LPC.platform}
extends   = common_LPC
board     = nxp_lpc1768

...

#
# Native
# No supported Arduino libraries, base Marlin only
#
[env:linux_native]
platform        = native
framework       =
build_flags     = -D__PLAT_LINUX__ -std=gnu++17 -ggdb -g -lrt -lpthread -D__MARLIN_FIRMWARE__ -Wno-expansion-to-defined
src_build_flags = -Wall -IMarlin/src/HAL/LINUX/include
build_unflags   = -Wall
lib_ldf_mode    = off
lib_deps        =
src_filter      = ${common.default_src_filter} +<src/HAL/LINUX>

#
# BBAI
# No supported Arduino libraries, base Marlin only
# (ARMCortex-M4)
#
[env:bbai]
platform        = native
board           = BBAI
build_flags     = -D__PLAT_LINUX__ -std=gnu++17 -ggdb -g -lrt -lpthread -D__MARLIN_FIRMWARE__ -Wno-expansion-to-defined
src_build_flags = -Wall -IMarlin/src/HAL/LINUX/include
build_unflags   = -Wall
lib_ldf_mode    = off
lib_deps        =
src_filter      = ${common.default_src_filter} +<src/HAL/LINUX>