Bump to Espressif's ESP-IDF 6.1

[mikeysklar]

What

ESP32 boards now build with ESP-IDF 6.1 instead of 6.0.1.

Why

6.1 includes Espressif's fix for SD cards failing when reopened, which #11500 was patching by hand.

Hardware tested

Ubuntu 24.04 host. CIRCUITPY files matched their backups after updating.

Board	Commit	REPL	sha256	WiFi scan	ssl
Metro ESP32-S3	505a514	ok	ok	15 networks	ok
Metro ESP32-S2	7d55c54	ok	ok	8 networks	ok
P4 GPIO (rev < 3)	7d55c54	ok	ok	n/a	n/a
ESP32-C5 DevKitC-1 N8R8	505a514	ok	ok	30 networks	ok
Feather ESP32-C6 4MB	505a514	ok	ok	6 networks	ok, HTTPS GET 200

microSD over SPI, Metro ESP32-S3, 505a514	Result
256 KB write, read back	sha256 match
Mount, list, unmount, deinit	10 of 10

Test commands and C5 output

import os,gc,microcontroller as m,hashlib,binascii;print("VER",os.uname().version);print("CPU",m.cpu.frequency,m.cpu.temperature);h=hashlib.new("sha256",b"abc");print("SHA",binascii.hexlify(h.digest())[:16]);print("FS",len(os.listdir("/")));gc.collect();print("MEM",gc.mem_free())
import wifi,ssl;n=[x.ssid for x in wifi.radio.start_scanning_networks()];wifi.radio.stop_scanning_networks();print("WIFI",len(n),"networks");print("SSL",ssl.create_default_context() is not None)

VER 11.0.0-alpha.1-37-g505a514e4d on 2026-10-06
CPU 240000000 27.5
SHA b'ba7816bf8f01cfea'
FS 12
MEM 8263200
WIFI 30 networks
SSL True

Not tested on hardware
Chips	ESP32, C2, C3, C61, H2, P4 rev 3 (all build)
Features	BLE beyond C6 workflow advertising, ULP, deep sleep, SDMMC (sdioio), H2 48 MHz flash

ESP-IDF patches

adafruit/esp-idf branch circuitpython-v6.1 is upstream v6.1 plus these.

Patch	Status
Fix sleep without console	kept
Getter for PSRAM address	kept
48 MHz flash clock for ESP32-H2	kept
#ifdef fix in esp_lcd_io_parl.h	kept
Quiet the RMT warning from neopixel	kept
Let both ULP types be on at once	dropped, 6.1 does it

Build changes

6.1 moved and split some files, so the Makefile follows.

Change	Why
New paths for systimer and heap ROM scripts	moved in 6.1
P4 ROM scripts renamed (eco5 to plain, plain to eco0_4)	rev 3 is now the default
Link esp_hal_systimer	split out of hal in 6.1
Link esp_hal_regi2c, except ESP32, C2, C3, S3	split out of hal in 6.1; those four have it in ROM
New mbedtls library names	mbedtls 4.1 split them
Always link IDF libmbedtls.a	boards without WiFi failed to link
Find the BLE library the way IDF does	H2 library moved
Drop stale ULP comment in S2/S3 defaults	patch no longer needed
C5: CIRCUITPY_ULAB_OPTIMIZE_SIZE = 1 (from #11403)	see below

C5 firmware size

6.1's WiFi libraries push the C5 past its 2 MB firmware.

C5, ru translation	Free bytes
Before ulab flag	-2448
After ulab flag	3024

Cost: ulab array math up to 1.7x slower (#11403).

AI assistance

Made with Claude Code. I reviewed the diff and ran every hardware test myself.

[dhalbert]

This looks good to me, and the testing is very helpful.