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[esp32_ble] Enable CONFIG_BT_RELEASE_IRAM on ESP32-C2#14109

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esp32c2-ble-release-iram
Feb 19, 2026
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[esp32_ble] Enable CONFIG_BT_RELEASE_IRAM on ESP32-C2#14109
bdraco merged 2 commits intodevfrom
esp32c2-ble-release-iram

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@bdraco bdraco commented Feb 19, 2026 •
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What does this implement/fix?

Enable CONFIG_BT_RELEASE_IRAM automatically when BLE is used on ESP32-C2 variants.

https://docs.espressif.com/projects/esp-idf/en/v5.2/esp32c2/api-guides/performance/ram-usage.html

The ESP32-C2 has very limited RAM (~272KB). Without this sdkconfig option, esp_bt_controller_init fails with ESP_ERR_NO_MEM, making BLE completely non-functional on C2 chips.

On ESP32-C2, enabling CONFIG_BT_RELEASE_IRAM disables CONFIG_ESP_SYSTEM_PMP_IDRAM_SPLIT, which changes the memory partitioning so IRAM and DRAM share space more flexibly. This gives the BT controller enough contiguous memory to initialize without OOM. The option also enables releasing ~21KB of BT IRAM via esp_bt_mem_release() after Bluetooth is no longer needed, but ESPHome keeps BLE running continuously (for proxy, improv, etc.) so that function is never called. The benefit here is purely from the compile-time memory layout change.

This is automatically applied during final validation when the ESP32-C2 variant is detected, so users no longer need to manually add it to their sdkconfig_options.

Types of changes

  • Bugfix (non-breaking change which fixes an issue)
  • New feature (non-breaking change which adds functionality)
  • Breaking change (fix or feature that would cause existing functionality to not work as expected)
  • Developer breaking change (an API change that could break external components)
  • Code quality improvements to existing code or addition of tests
  • Other

Related issue or feature (if applicable):

Pull request in esphome-docs with documentation (if applicable):

  • N/A (no user-facing configuration changes)

Test Environment

  • ESP32
  • ESP32 IDF
  • ESP8266
  • RP2040
  • BK72xx
  • RTL87xx
  • LN882x
  • nRF52840

Example entry for config.yaml:

# No changes needed - CONFIG_BT_RELEASE_IRAM is now set automatically on ESP32-C2
# Previously users had to manually add:
#   esp32:
#     framework:
#       type: esp-idf
#       sdkconfig_options:
#         CONFIG_BT_RELEASE_IRAM: y

Checklist:

  • The code change is tested and works locally.
  • Tests have been added to verify that the new code works (under tests/ folder).

If user exposed functionality or configuration variables are added/changed:

@bdraco @claude
[esp32_ble] Enable CONFIG_BT_RELEASE_IRAM on ESP32-C2
f3e3a81 
The ESP32-C2 has very limited RAM (~272KB) and BLE initialization
fails with ESP_ERR_NO_MEM without this option. CONFIG_BT_RELEASE_IRAM
frees ~21KB of IRAM by merging BT text/data/bss into heap, which is
enough for BLE to work on the memory-constrained C2.

Closes #13516

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Copilot AI review requested due to automatic review settings February 19, 2026 16:55
@bdraco bdraco requested a review from jesserockz as a code owner February 19, 2026 16:55
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github-actions bot commented Feb 19, 2026

👋 Hi there! This PR modifies 1 file(s) with codeowners.

@jesserockz, @Rapsssito - As codeowner(s) of the affected files, your review would be appreciated! 🙏

Note: Automatic review request may have failed, but you're still welcome to review.

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github-actions bot commented Feb 19, 2026

To use the changes from this PR as an external component, add the following to your ESPHome configuration YAML file:

external_components:
  - source: github://pr#14109
    components: [esp32_ble]
    refresh: 1h

(Added by the PR bot)

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codecov-commenter commented Feb 19, 2026 •
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Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 74.11%. Comparing base (bd50b80) to head (859b434).
⚠️ Report is 4 commits behind head on dev.

Additional details and impacted files 
@@           Coverage Diff           @@
##              dev   #14109   +/-   ##
=======================================
  Coverage   74.11%   74.11%           
=======================================
  Files          55       55           
  Lines       11590    11590           
  Branches     1578     1578           
=======================================
  Hits         8590     8590           
  Misses       2598     2598           
  Partials      402      402

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

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  • ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.

swoboda1337
swoboda1337 previously approved these changes Feb 19, 2026
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@swoboda1337 swoboda1337 added this to the 2026.2.1 milestone Feb 19, 2026
Copilot AI reviewed Feb 19, 2026
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Pull request overview

This PR fixes BLE functionality on ESP32-C2 devices by automatically enabling the CONFIG_BT_RELEASE_IRAM sdkconfig option. The ESP32-C2 has limited RAM (~272KB), and without this option, esp_bt_controller_init fails with ESP_ERR_NO_MEM. The fix enables this option automatically during final validation when the ESP32-C2 variant is detected, eliminating the need for users to manually configure it.

Changes:

  • Added automatic CONFIG_BT_RELEASE_IRAM configuration for ESP32-C2 to free ~21KB of IRAM required for BLE operation
  • Added test coverage for ESP32-C2 BLE functionality

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File Description
tests/components/esp32_ble/test.esp32-c2-idf.yaml New test file for ESP32-C2 BLE functionality following the established test pattern
esphome/components/esp32_ble/init.py Added import of VARIANT_ESP32C2 constant and conditional sdkconfig option setting in final_validation

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github-actions bot commented Feb 19, 2026 •
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Memory Impact Analysis

Components: esp32_ble
Platform: esp32-idf

Metric Target Branch This PR Change
RAM 33,500 bytes 33,500 bytes ➡️ +0 bytes (0.00%)
Flash 573,911 bytes 573,911 bytes ➡️ +0 bytes (0.00%)

Note: This analysis measures static RAM and Flash usage only (compile-time allocation).
Dynamic memory (heap) cannot be measured automatically.
⚠️ You must test this PR on a real device to measure free heap and ensure no runtime memory issues.

This analysis runs automatically when components change. Memory usage is measured from a representative test configuration.

@bdraco
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bdraco commented Feb 19, 2026

thanks

@bdraco bdraco enabled auto-merge (squash) February 19, 2026 17:09
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bdraco commented Feb 19, 2026

oops. I reset instead of pushing the CONFIG_ESP_SYSTEM_PMP_IDRAM_SPLIT change on top

@bdraco @claude
[esp32_ble] Disable PMP IDRAM split for BT IRAM release on ESP32-C2
859b434 
CONFIG_BT_RELEASE_IRAM requires CONFIG_ESP_SYSTEM_PMP_IDRAM_SPLIT to
be disabled, otherwise ESP-IDF raises a compile-time error.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
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bdraco commented Feb 19, 2026

should have just let claude do it :)

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bdraco commented Feb 19, 2026

all good now

Wrote 0xa58c0 bytes to file '/Users/bdraco/esphome/tests/test_build_components/build/.esphome/build/componenttestesp32c2idf/.pioenvs/componenttestesp32c2idf/firmware.factory.bin', ready to flash to offset 0x0.
Successfully created /Users/bdraco/esphome/tests/test_build_components/build/.esphome/build/componenttestesp32c2idf/.pioenvs/componenttestesp32c2idf/firmware.factory.bin
esp32_copy_ota_bin([".pioenvs/componenttestesp32c2idf/firmware.bin"], [".pioenvs/componenttestesp32c2idf/firmware.elf"])
Copied firmware to /Users/bdraco/esphome/tests/test_build_components/build/.esphome/build/componenttestesp32c2idf/.pioenvs/componenttestesp32c2idf/firmware.ota.bin
==================================================================================================== [SUCCESS] Took 23.46 seconds ====================================================================================================
INFO Build Info: config_hash=0x59987129 build_time_str=2026-02-19 11:18:43 -0600

@bdraco bdraco merged commit 7a5c3ce into dev Feb 19, 2026
26 checks passed
@bdraco bdraco deleted the esp32c2-ble-release-iram branch February 19, 2026 17:41
swoboda1337 pushed a commit that referenced this pull request Feb 20, 2026
@bdraco @claude @swoboda1337
[esp32_ble] Enable CONFIG_BT_RELEASE_IRAM on ESP32-C2 (#14109)
d784963 
Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>
@swoboda1337 swoboda1337 mentioned this pull request Feb 20, 2026
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BLE not working with ESP32C2

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