ESP32 Thread Border Router Board with 4MB flash

[bonzo-dog]

I very recently bought the Espressif Thread Border Router board (h/w V1.2) and have been using firmware Release 1.2
This works rather well.
However, the board only has 4MB flash for the ESP32-S3, and Release 1.3 won't fit in a 4MB flash
(the 2 OTA partitions are 2M each, for example)
Could someone aid me in how to reduce the size of Release 1.3, hopefully without having to remove the webserver functionality?
I think I need to play around with the OTA partition(s) size, but am unsure exactly what I need to do ...
Any help would be appreciated :)

[tanyanquan]

Hi @bonzo-dog , thanks for your question!

Here are the steps which you can try (starting with a clean folder, i.e. idf.py fullclean):

1. Change the following options in examples/basic_thread_border_router/sdkconfig.defaults
   • Replace CONFIG_ESPTOOLPY_FLASHSIZE_8MB with CONFIG_ESPTOOLPY_FLASHSIZE_4MB
   • Add this line at the end: CONFIG_LOG_DEFAULT_LEVEL_NONE=y
2. Change the OTA partitions to use 1500K instead of 2M each
3. build erase-flash flash monitor as per usual

If you find a need to reduce the binary size even further, please refer to: https://docs.espressif.com/projects/esp-idf/en/latest/esp32s3/api-guides/performance/size.html#reducing-overall-size

Please feel free to reach out if you need any other assistance!

[bonzo-dog]

Thank you for that information. That worked :)

[zwx1995esp]

FYI @bonzo-dog We have two hardware revisions of the TBR V1.2 board.

• In the original version, we use the S3 MCN4R2 variant, which has 4 MB of flash.
• In the latest version, we use the S3 MCN8R2 variant, which has 8 MB of flash.

The reason we changed the S3 variant is that we found 4 MB of flash is quite limited for the TBR to perform OTA together with RCP updates. So if you plan to build your own applications and design your product, we recommend using the latest version.

[Traumtandler]

I tried to follow this guide, but now get the following error:
Error: All app partitions are too small for binary esp_ot_br.bin size 0x182e40:

• Part 'ota_0' 0/16 @ 0x20000 size 0x177000 (overflow 0xbe40)
• Part 'ota_1' 0/17 @ 0x1a0000 size 0x177000 (overflow 0xbe40)

1. I found sdkconfig.defaults and made the changes as per 1. above
2. I was unsure of how to change the partitions size. I changed partitions.csv. The relevant lines now are:
   ota_0, app, ota_0, , 1500K,
   ota_1, app, ota_1, , 1500K,

Do I also need to change the offset? What about otadata?

[zwx1995esp]

Yes, you may increase the size of the partition ota_0 and ota_1.

[Traumtandler]

Yes, I know I can increase it - if I have a 8MB version of the board. However, I have a 4 MB board, which I am trying to get to work.
I tried ordering a 8MB version, but your distributers either sell the 4MB version (Digikey) or don't specify which version they sell (Mouser). I don't want to buy quantties of boards in the hope of finding the odd 8MB board .
I don't think it is good policy to sell two different boards under the same product code and then publish code on github which only works with one variant.
Can you be more specific on how to change the OTA partitions? How do I get the 4MB version to work?
Alternatively, how can I buy a board and be sure to get the 8MB version?