Uploading cfg.json & presets.json via pio's Upload Filesystem Image does not work

[UsableLoki8221]

What happened?

Previously I would flash the filesystem with premade config and presets file in wled00/data in 16.0.0 and this would work well. Now I noticed it has not been working on the most recent nightly source.

To Reproduce Bug

Backup cfg/presets to wled00/data/ and upload via run --target uploadfs --environment esp32c3dev and notice no settings are applied on startup

Expected Behavior

cfg and presets should be applied

Install Method

Self-Compiled

What version of WLED?

Installed version: WLED 17.0.0-devV5 (2607201) "ESP32-C3-QIO"

Which microcontroller/board are you seeing the problem on?

ESP32-C3

Relevant log/trace output

Anything else?

No response

Code of Conduct

• I agree to follow this project's Code of Conduct

[softhack007]

Previously I would flash the filesystem with premade config and presets file in wled00/data in 16.0.0 and this would work well. Now I noticed it has not been working on the most recent nightly source.

@UsableLoki8221 uploading "data" is not supported any more since a long time - at least since WLED 0.13.x. WLED generates compressed HTML source files from the content of "data". This folder is not intended for supplying a user-defined cfg.json or presets.json.

Edit: pio run --target uploadfs is not supported either, because it will most likely generate a SPIFFS filesystem, instead of LittleFS. This explains your observations with WLED 17.0.0-devV5 - the SPIFFS driver was removed in the new framework we use in 17.0.0.

[softhack007]

PRs that might be related:

• Add factory binary generation for release builds #5712
• Implement combined factory bin creation with filesystem support #5274
• Build setup: minimal fs_data + override example MoonModules/WLED-MM#343

[UsableLoki8221]

Weird, I was definitely pulling it off in 16.0.0 adequately:

Executing task: C:\Users\Vero\.platformio\penv\Scripts\platformio.exe run --target uploadfs --environment esp32c3dev_qio 

Processing esp32c3dev_qio (platform: https://github.com/tasmota/platform-espressif32/releases/download/2024.06.00/platform-espressif32.zip; framework: arduino; board: esp32-c3-devkitm-1)
--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------Verbose mode can be enabled via `-v, --verbose` option
*** use existing my_config.h ***
Installing node packages
npm ci

added 66 packages, and audited 67 packages in 1s

14 packages are looking for funding
  run `npm fund` for details

2 high severity vulnerabilities

To address all issues, run:
  npm audit fix

Run `npm audit` for details.
npm run build

> wled@16.0.0-alpha build
> node tools/cdata.js


          ##  ##      ##        ######    ######
        ##      ##    ##      ##        ##  ##  ##
        ##  ##  ##  ##        ######        ##  ##
        ##  ##  ##  ##        ##            ##  ##
          ##  ##      ######    ######    ######
                 build script for web UI

Web UI is already built
CONFIGURATION: https://docs.platformio.org/page/boards/espressif32/esp32-c3-devkitm-1.html
PLATFORM: Espressif 32 (2024.6.0) > Espressif ESP32-C3-DevKitM-1
HARDWARE: ESP32C3 160MHz, 320KB RAM, 4MB Flash
DEBUG: Current (cmsis-dap) External (cmsis-dap, esp-bridge, esp-builtin, esp-prog, iot-bus-jtag, jlink, minimodule, olimex-arm-usb-ocd, olimex-arm-usb-ocd-h, olimex-arm-usb-tiny-h, olimex-jtag-tiny, tumpa)
PACKAGES: 
 - framework-arduinoespressif32 @ 2.0.18+sha.8ba0dc0 
 - tool-esptoolpy @ 4.7.4 
 - tool-mkfatfs @ 2.0.1 
 - tool-mklittlefs @ 3.2.0 
 - toolchain-riscv32-esp @ 8.4.0+2021r2-patch5
LDF: Library Dependency Finder -> https://bit.ly/configure-pio-ldf
LDF Modes: Finder ~ chain, Compatibility ~ strict
Found 38 compatible libraries
Scanning dependencies...
Dependency Graph
|-- AsyncTCP @ 3.4.7
|-- AnimatedGIF @ 1.4.7
|-- GifDecoder @ 1.1.0+sha.bc3af18
|-- esp_dmx @ 3.1.1+sha.47db25d8
|-- FastLED @ 3.6.0
|-- IRremoteESP8266 @ 2.8.2
|-- NeoPixelBus @ 2.8.4+sha.a0919d1
|-- ESPAsyncWebServerWLED @ 2.4.2+sha.39b830c
|-- AsyncMqttClient @ 0.9.0
|-- QuickEspNow @ 0.8.1+sha.193e991
|-- ESPmDNS @ 2.0.0
|-- Wire @ 2.0.0
|-- Update @ 2.0.0
|-- ArduinoOTA @ 2.0.0
|-- DNSServer @ 2.0.0
|-- Ethernet @ 2.0.0
|-- LittleFS @ 2.0.0
|-- SPI @ 2.0.0
|-- WiFi @ 2.0.0
|-- NeoESP32RmtHI
|-- ESP32 Async UDP @ 2.0.0
|-- WebServer @ 2.0.0
Building in release mode
Building FS image from 'wled00\data' directory to .pio\build\esp32c3dev_qio\littlefs.bin
/404.htm
/cfg.json
/common.js
/cpal/cpal.htm
/dmxmap.htm
/edit.htm
/favicon.ico
/icons-ui/demo-files/demo.css
/icons-ui/demo-files/demo.js
/icons-ui/demo.html
/icons-ui/fonts/wled122.woff
/icons-ui/fonts/wled122.woff2
/icons-ui/Read Me.txt
/icons-ui/selection.json
/icons-ui/style.css
/index.css
/index.htm
/index.js
/iro.js
/liveview.htm
/liveviewws2D.htm
/msg.htm
/pixart/boxdraw.js
/pixart/favicon-16x16.png
/pixart/favicon-32x32.png
/pixart/favicon.ico
/pixart/getPixelValues.js
/pixart/pixart.css
/pixart/pixart.htm
/pixart/pixart.js
/pixart/site.webmanifest
/pixart/statics.js
/pixelforge/omggif.js
/pixelforge/pixelforge.htm
/presets.json
/pxmagic/pxmagic.htm
/rangetouch.js
/settings.htm
/settings_2D.htm
/settings_dmx.htm
/settings_leds.htm
/settings_pin.htm
/settings_pininfo.htm
/settings_sec.htm
/settings_sync.htm
/settings_time.htm
/settings_ui.htm
/settings_um.htm
/settings_wifi.htm
/style.css
/update.htm
/usermod.htm
/welcome.htm
Looking for upload port...
Auto-detected: COM15
Uploading .pio\build\esp32c3dev_qio\littlefs.bin
esptool.py v4.7.4
Serial port COM15
Connecting...
Chip is ESP32-C3 (QFN32) (revision v0.4)
Features: WiFi, BLE, Embedded Flash 4MB (XMC)
Crystal is 40MHz
MAC: f8:5b:1b:22:ab:44
Uploading stub...
Running stub...
Stub running...
Changing baud rate to 460800
Changed.
Configuring flash size...
Auto-detected Flash size: 4MB
Flash will be erased from 0x00310000 to 0x003fffff...
Compressed 983040 bytes to 199317...
Writing at 0x00310000... (7 %)
Writing at 0x003224e0... (15 %)
Writing at 0x00332fe6... (23 %)
Writing at 0x00344eda... (30 %)
Writing at 0x00353913... (38 %)
Writing at 0x00365130... (46 %)
Writing at 0x0039e872... (53 %)
Writing at 0x003b7325... (61 %)
Writing at 0x003c41b6... (69 %)
Writing at 0x003d3027... (76 %)
Writing at 0x003e07a0... (84 %)
Writing at 0x003eccda... (92 %)
Writing at 0x003fc7ae... (100 %)
Wrote 983040 bytes (199317 compressed) at 0x00310000 in 3.3 seconds (effective 2399.2 kbit/s)...
Hash of data verified.

Leaving...
Hard resetting via RTS pin...
======================================================================================== [SUCCESS]`

However, in the newest version I just noticed that flashing the filesystem isn't running the "Building FS image from 'wled00\data' directory to .pio\build\esp32c3dev_qio\littlefs.bin" message:

executing task: C:\Users\Vero\.platformio\penv\Scripts\platformio.exe run --target uploadfs --environment esp32c3dev_qio 

Processing esp32c3dev_qio (board: esp32-c3-devkitm-1; platform: https://github.com/tasmota/platform-espressif32/releases/download/2026.05.50/platform-espressif32.zip; framework: arduino)
--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------Verbose mode can be enabled via `-v, --verbose` option
*** use existing my_config.h ***
Installing node packages
npm ci

added 66 packages, and audited 67 packages in 974ms

14 packages are looking for funding
  run `npm fund` for details

found 0 vulnerabilities
npm run build

> wled@17.0.0-devV5 build
> node tools/cdata.js


          ##  ##      ##        ######    ######
        ##      ##    ##      ##        ##  ##  ##
        ##  ##  ##  ##        ######        ##  ##
        ##  ##  ##  ##        ##            ##  ##
          ##  ##      ######    ######    ######
                 build script for web UI

Web UI is already built
CONFIGURATION: https://docs.platformio.org/page/boards/espressif32/esp32-c3-devkitm-1.html
PLATFORM: Espressif 32 (2026.5.50) > Espressif ESP32-C3-DevKitM-1
HARDWARE: ESP32C3 160MHz, 320KB RAM, 4MB Flash
DEBUG: Current (cmsis-dap) External (cmsis-dap, esp-bridge, esp-builtin, esp-prog, esp-prog-2, iot-bus-jtag, jlink, minimodule, olimex-arm-usb-ocd, olimex-arm-usb-ocd-h, olimex-arm-usb-tiny-h, olimex-jtag-tiny, tumpa)
PACKAGES: 
 - contrib-piohome @ 3.4.4 
 - framework-arduinoespressif32 @ 3.3.8+sha.f2a3fa2b 
 - tool-esp-rom-elfs @ 2024.10.11 
 - tool-esptoolpy @ 5.2.0 
 - tool-riscv32-esp-elf-gdb @ 16.3.0+20250913 
 - toolchain-riscv32-esp @ 15.2.0+20251204
LDF: Library Dependency Finder -> https://bit.ly/configure-pio-ldf
LDF Modes: Finder ~ off, Compatibility ~ strict
Found 43 compatible libraries
Scanning dependencies...
Dependency Graph
|-- AsyncTCP @ 3.4.10
|-- AnimatedGIF @ 1.4.7
|-- GifDecoder @ 1.1.0+sha.bc3af18
|-- esp_dmx @ 4.1.0+sha.ed12a29
|-- IRremoteESP8266 @ 2.9.0
|-- ESPAsyncWebServerWLED @ 2.4.2+sha.ac44e32
|-- AsyncMqttClient @ 0.9.0
|-- NeoPixelBus @ 2.9.0+sha.76afe83
|-- audioreactive
|-- auto_save
Building in release mode
Building FS image from 'wled00\data' directory to .pio\build\esp32c3dev_qio\littlefs.bin
Looking for upload port...
Auto-detected: COM15
Uploading .pio\build\esp32c3dev_qio\littlefs.bin
esptool v5.2.0
Serial port COM15:
Connecting...
Connected to ESP32-C3 on COM15:
Chip type:          ESP32-C3 (QFN32) (revision v0.4)
Features:           Wi-Fi, BT 5 (LE), Single Core, 160MHz, Embedded Flash 4MB (XMC)
Crystal frequency:  40MHz
USB mode:           USB-Serial/JTAG
MAC:                f8:5b:1b:22:ab:44

Uploading stub flasher...
Running stub flasher...
Stub flasher running.
Changing baud rate to 460800...
Changed.

Configuring flash size...
Auto-detected flash size: 4MB
Flash will be erased from 0x00310000 to 0x003fffff...
Compressed 983040 bytes to 220316...

Writing at 0x00310000 [░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░]   0.0% 0/220316 bytes... 

Writing at 0x00321f17 [██░░░░░░░░░░░░░░░░░░░░░░░░░░░░]   7.4% 16384/220316 bytes... 

Writing at 0x00345225 [████░░░░░░░░░░░░░░░░░░░░░░░░░░]  14.9% 32768/220316 bytes... 

Writing at 0x00352ffb [██████░░░░░░░░░░░░░░░░░░░░░░░░]  22.3% 49152/220316 bytes... 

Writing at 0x00360112 [████████░░░░░░░░░░░░░░░░░░░░░░]  29.7% 65536/220316 bytes... 

Writing at 0x0036e03c [███████████░░░░░░░░░░░░░░░░░░░]  37.2% 81920/220316 bytes... 

Writing at 0x00384025 [█████████████░░░░░░░░░░░░░░░░░]  44.6% 98304/220316 bytes... 

Writing at 0x00394638 [███████████████░░░░░░░░░░░░░░░]  52.1% 114688/220316 bytes... 

Writing at 0x003a6877 [█████████████████░░░░░░░░░░░░░]  59.5% 131072/220316 bytes... 

Writing at 0x003b65d9 [████████████████████░░░░░░░░░░]  66.9% 147456/220316 bytes... 

Writing at 0x003cc7ec [██████████████████████░░░░░░░░]  74.4% 163840/220316 bytes... 

Writing at 0x003dd1dd [████████████████████████░░░░░░]  81.8% 180224/220316 bytes... 

Writing at 0x003ebda6 [██████████████████████████░░░░]  89.2% 196608/220316 bytes... 

Writing at 0x003fa936 [█████████████████████████████░]  96.7% 212992/220316 bytes... 

Writing at 0x00400000 [██████████████████████████████] 100.0% 220316/220316 bytes... 
Wrote 983040 bytes (220316 compressed) at 0x00310000 in 3.3 seconds (2385.7 kbit/s).
Verifying written data...
Hash of data verified.

Hard resetting via RTS pin...
======================================================================================== [SUCCESS]

[softhack007]

As I explained - pio filesystem upload is not supported for WLED, even if the feature exists in PlatformIO. Its a "may or may not work" thing.

Edit: Building FS image from 'wled00\data' directory to .pio\build\esp32c3dev_qio\littlefs.bin ... Wrote 983040 bytes
means that you override the compressed web UI files with a bloated collection of uncompressed files. This can be useful for WebUI debugging, but its definitely not meant for "production".

[UsableLoki8221]

So I flashed WLED 17.0.0-devV5 (2607201) and then used my previous 16.0.0 environment where I copied the contents of wled00/data from 17 into and ran the filesystem and it worked. So I think that something's gotten messed up in the newer environment where pio's filesystem command doesn't catch any files after Building FS image from 'wled00\data' directory to .pio\build\esp32c3dev_qio\littlefs.bin

[softhack007]

@UsableLoki8221 again - you're doing something which is not officially supported, and actually its very much discouraged to create and upload a huge filesystem in the way you explain. I see no need to "fix it", because we never said it would work. Period.

[UsableLoki8221]

@softhack007 How is uploading the filesystem not supported? Its just platformio core functionality that's someone previously configured to upload whatever is in wled00/data from the environment.

Regardless of your impatience I am genuinely trying to point out the discrepancy and be helpful- I figured out why the filesystem uploader stopped working in the latest environment compared to the previous:
previously littleFS (<17.0) used "mklittlefs" -c wled00\data -s 983040 -p 256 -b 4096 .pio\build\esp32c3dev_qio\littlefs.bin. to build the fs binary.

The new littleFS (17.0) uses build_fs_router([".pio\build\esp32c3dev_qio\littlefs.bin"], ["wled00\data"]) which fails to actually make a binary from files in that location.

I already wrote myself a script that uses the previous filesystem binary tool so I'm happy- if what I found is helpful then make of that what you will. Period.

[softhack007]

@softhack007 How is uploading the filesystem not supported? Its just platformio core functionality

@UsableLoki8221 sorry if I appear impatient. What your proposing is actually a dangerous hack, and I'm obviously struggling to make myself clear on the "why".

• a normal WLED build - without FS creation - stores all *htm, *.js, *.css files from wled00/data inside the firmware; files are compressed and inlined into header files. The web server reads these directly from the firmware (read-only), instead of accessing the filesystem.

• "uploading the filesystem" creates a huge copy of the same data - in your case, it seems to be ~980Kb, so uploading to a 4MB board may fail due to image size. You might very soon face "out of file space" problems when saving new presets.

• the huge copy overwrites everything that is stored inside the firmware. OTA updates may leave you with a broken UI, because firmware and WebUI do not fit together any more

• uncompressed files on the filesystem cause userinterface slowdown

• overwiting the build-in userinterface by littleFS files can lead to LEDs flickering during file reading, particularly bad on -C3.

All this lead to a design decision (around the time of WLED 0.13.0) of not using filesystem upload (from wled00/data) in WLED. Even when platformIO allows it, WLED builds would become unreliable, 4MB boards will have problems, and OTA updates can lead to a corrupted user interface. Hence the development team consideres it "not supported".

I hope you understood me better now.

[UsableLoki8221]

I imagine that maybe it was used since littleFS is directing to the wled00 folder instead of a root /data folder so someone purposely pointed littleFS to that location at one point. What I posted was a plain example but now I strictly just upload the cfg.json and presets.json and not all those .htm files and it works great. It was something that worked previously but now didn't. In the end, the main purpose/benefit is to seamlessly upload existing settings as the firmware is getting flashed.

…

On Mon, Sep 7, 2026, 11:59 AM Frank Möhle ***@***.***> wrote: *softhack007* left a comment (wled/WLED#5839) <#5839 (comment)> As I explained - pio filesystem upload is not supported, even if the feature exists in PlatformIO. Its a "may or may not work" thing. — Reply to this email directly, view it on GitHub <#5839?email_source=notifications&email_token=BJ6AZMCVAOGY6JC3ISERPMD5N3LN5A5CNFSNUABFM5UWIORPF5TWS5BNNB2WEL2JONZXKZKDN5WW2ZLOOQXTKNJXGMYTENJZGUYKM4TFMFZW63VHNVSW45DJN5XKKZLWMVXHJLDGN5XXIZLSL5RWY2LDNM#issuecomment-5573125950>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/BJ6AZMC4HPZSJLEVEWL7MCD5N3LN5AVCNFSNUABEKJSXA33TNF2G64TZHM3TMOJZGAZDAOJ3JFZXG5LFHM2TGNZVGUZTMNZUGGQXMAQ> . Triage notifications, keep track of coding agent tasks and review pull requests on the go with GitHub Mobile for iOS <https://github.com/notifications/mobile/ios/BJ6AZMBGK4MCP6JDXN7DU435N3LN5A5CNFSNUABFM5UWIORPF5TWS5BNNB2WEL2JONZXKZKDN5WW2ZLOOQXTKNJXGMYTENJZGUYKM4TFMFZW63VHNVSW45DJN5XKKZLWMVXHJKTGN5XXIZLSL5UW64Y> and Android <https://github.com/notifications/mobile/android/BJ6AZMBUR4MGIQD7SCQ2VBT5N3LN5A5CNFSNUABFM5UWIORPF5TWS5BNNB2WEL2JONZXKZKDN5WW2ZLOOQXTKNJXGMYTENJZGUYKM4TFMFZW63VHNVSW45DJN5XKKZLWMVXHJLTGN5XXIZLSL5QW4ZDSN5UWI>. Download it today! You are receiving this because you were mentioned.Message ID: ***@***.***>