All opportunities to reduce firmware size on ESP32

[AmirHmZz]

It would be nice to have a list of all opportunities to reduce firmware size to a minimum.

Here's some config I've tried already (from sdkconfig.d2wd):

CONFIG_COMPILER_OPTIMIZATION_SIZE=y
CONFIG_COMPILER_OPTIMIZATION_PERF=n
CONFIG_COMPILER_OPTIMIZATION_CHECKS_SILENT=y

CONFIG_LOG_MAXIMUM_LEVEL_ERROR=y
CONFIG_LOG_MAXIMUM_LEVEL_INFO=n

CONFIG_ETH_USE_SPI_ETHERNET=n

Is there anyway to disable these features:

• Bluetooth
• TLS
• lwIP
• micropython compiler

[felixdoerre]

You didn't specify which firmware variant you are using. For most of those features there are compiler flags, and they are disabled in some of the boards:

• bluetooth: MICROPY_PY_BLUETOOTH, see e.g. this board, which has it disabled:
  https://github.com/micropython/micropython/blob/master/ports/esp32/boards/LOLIN_S2_MINI/mpconfigboard.h#L5
• TLS: MICROPY_PY_SSL and MICROPY_SSL_MBEDTLS
• lwip: this is not provided by micropython but instead used from the esp-idf. Micropython just implements a python interface to it: https://github.com/micropython/micropython/blob/fa23e4b093f81f03a24187c7ea0c928a9b4a661b/ports/esp32/modsocket.c. I don't see a macro to disable that interface, so maybe there is a flag missing there.
• micropython compiler: MICROPY_ENABLE_COMPILER

if you want to adjust ESP32_GENERIC, you could add those flags here: https://github.com/micropython/micropython/blob/master/ports/esp32/boards/ESP32_GENERIC/mpconfigboard.h

[AmirHmZz]

I've tried to disable TLS by setting MICROPY_PY_SSL and MICROPY_SSL_MBEDTLS to 0
but it seems cryptolib and hashlib should be excluded too.

[felixdoerre]

For that there is MICROPY_PY_CRYPTOLIB and MICROPY_PY_HASHLIB

[AmirHmZz]

Done. Now I'm struggling disabling MICROPY_PY_BTREE but it is throwing errors on build time.

[jonnor]

What is your current image size, and what is your target?

[AmirHmZz]

it is currently 1.26MB. It would be great to reduce it under 1MB.

What I've already tried:

MICROPY_OPT_COMPUTED_GOTO=0
MICROPY_PY_NETWORK_LAN=0
MICROPY_PY_BLUETOOTH=0
MICROPY_PY_SSL=0
MICROPY_SSL_MBEDTLS=0
MICROPY_PY_CRYPTOLIB=0
MICROPY_PY_HASHLIB=0
MICROPY_PY_WEBSOCKET=0
MICROPY_PY_WEBREPL=0
MICROPY_PY_MACHINE_I2S=0

[shariltumin]

You can try to reduce the number of frozen modules in your firmware. Try using this "manifest.py" in your "ports/esp32/boards" directory.

freeze("$(PORT_DIR)/modules")
# --include("$(MPY_DIR)/extmod/asyncio")

# Useful networking-related packages.
# --require("bundle-networking")
require("mip")
require("ntptime")
# --require("ssl")
require("requests")
# --require("webrepl")

# Provide urequests (which just forwards to requests) for backwards
# compatibility.
# --require("urequests")

# Require some micropython-lib modules.
# --require("aioespnow")
require("dht")
require("ds18x20")
require("neopixel")
require("onewire")
require("umqtt.robust")
require("umqtt.simple")
# --require("upysh")

It is up to you to choose which modules to include or exclude.

[xyzzy42]

It's possible to turn PPP off, #13640

And here's some more things you can turn off:

#define MICROPY_HW_ENABLE_SDCARD            (0)
#define MICROPY_PY_MACHINE_DAC              (0)
#define MICROPY_PY_MACHINE_I2S              (0)
#define MICROPY_PY_ESPNOW                   (0)
#define MICROPY_PY_NETWORK_LAN              (0)

ESP-IDF is configurable and things can be turned off there too. Try CONFIG_ETH_USE_SPI_ETHERNET and CONFIG_LWIP_PPP_SUPPORT. Also flash chip types you aren't using.