Basic rBoot


This sample integrates rBoot and Sming, for the many people who have been asking for it. It demonstrates dual rom booting, big flash support, OTA updates and dual spiffs filesystems. You must enable big flash support in rBoot and use on an ESP12 (or similar device with 4MB flash). When using rBoot big flash support with multiple 1MB slots only one rom image needs to be created. If you don’t want to use big flash support (e.g. for a device with smaller flash) see the separate instructions below. You can easily take the ota files and add them to your own project to add OTA support.


  1. Set ESP_HOME & SMING_HOME, as environment variables or edit as you would for general Sming app compiling.
  2. Set WIFI_SSID & WIFI_PWD environment variables with your wifi details.
  3. Edit the OTA server details at the top of app/application.cpp.
  4. Check overridable variables in, or set as env vars.
  5. make && make flash
  6. Put rom0.bin and spiff_rom.bin in the root of your webserver for OTA.
  7. Interact with the sample using a terminal (make terminal). Sorry - no web-gui (yet).


If flashing manually use to flash rBoot, rom & spiffs e.g.: –port write_flash -fs 32m 0x00000 rboot.bin 0x02000 rom0.bin 0x100000 spiffs.rom

Using the correct -fs parameter is important. This will be -fs 32m on an ESP12.

You can also flash rom0.bin to 0x202000, but booting and using OTA is quicker!

Technical Notes

spiffs_mount_manual(address, length) must be called from init.

Important compiler flags used:

  • BOOT_BIG_FLASH - when using big flash mode, ensures flash mapping code is built in to the rom.
  • RBOOT_INTEGRATION - ensures Sming specific options are pulled in to the rBoot source at compile time.
  • SPIFF_SIZE=value - passed through to code for mounting the filesystem. Also used in the Makefile to create the SPIFFS.

Flash layout considerations

If you want to use, for example, two 512k roms in the first 1MB block of flash (old style) then Sming will automatically create two separately linked roms. If you are flashing a single rom to multiple 1MB flash blocks, all using the same offset inside their 1MB blocks, only a single rom is created. See the rBoot readme for further details.

  • If using a very small flash (e.g. 512k) there may be no room for a spiffs fileystem, disable it with DISABLE_SPIFFS = 1
  • If you are using spiffs set RBOOT_SPIFFS_0 & RBOOT_SPIFFS_1 to indicate where the filesystems are located on the flash.
  • After building copy all the rom*.bin files to the root of your web server.

If you want more than two roms you must be an advanced user and should be able to work out what to copy and edit to acheive this!


This sample was made possible with the assistance of piperpilot, gschmott and robotiko on the forum.