Hosting OpenBekenIOT Web App's 'Logs' function in the LittleFS of the Device (BK7231T)

jkwim 5292 60

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OTA can wipe LittleFS, so keep a backup; if that happens you can recreate the filesystem with `lfs_format` at the size you need [#20928195] The main size issue is not OTA itself but device memory: LittleFS uses 4 KB blocks, so oversized partitions can trigger low-heap warnings or reboots, and the upload/copy path needed an RTOS delay fix to become stable [#20930090][#20931820][#20941452] In the end, the web app was successfully hosted on-device with a `0x34000` (212 kB) LittleFS, minified `httpVueLoader`, and the required files including `filesystem.vue`, `logs.vue`, and the modified `startup.js`/`indexdevice.html` paths [#20944917] The author also found that minifying the `.vue` files let him shrink the partition and that 196 kB still worked, but 212 kB could still show low-heap warnings [#20946139][#20944917] So the practical recommendation is: enlarge LittleFS only as far as the device tolerates, expect OTA to erase it, and plan to restore the files afterward [#20928195][#20944940]

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#61 21654378 05 Sep 2025 20:40

p.kaczmarek2 p.kaczmarek2

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Post #61
21654378 05 Sep 2025 20:40

Ah, I see, a buffer. That's needed because SD card expects 3.3V voltage levels and your board supports 5V so it can be used with Arduino.

I am creating multiplatform open source firmware (Tasmota replacement), right now supporting BK7231T, BK7231N, XR809, BL602, W800, W600, LN882H and soon supporting RTL and W701:
https://github.com/openshwprojects/OpenBK7231T
If you like my work, support me at: https://paypal.me/openshwprojects

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Topic summary

The discussion focuses on hosting the OpenBekenIOT Web App's 'Logs' function within the device's LittleFS filesystem on BK7231T and BK7231N devices. The default LittleFS size is 32kB, which is insufficient for hosting multiple web app files such as startup.js, httpVueLoader.js, vue.min.js, and logs.vue. Users experimented with increasing LittleFS size up to 256kB and 200kB (0x32000), with mixed success due to device reboots and low heap warnings during large file uploads. A key finding was that adding RTOS delays during file upload improved stability, as implemented in a test firmware build. Firmware upgrades to versions around 1.17.404 and above were recommended for better performance. Minification of JavaScript and Vue files significantly reduced storage requirements, enabling hosting within the constrained LittleFS space. The memory layout of BK7231T and BK7231N devices was reviewed to understand partitioning and avoid overwriting OTA or application partitions. Alternative hosting solutions suggested include running the web app on a NAS or router with OpenWrt. Further development includes moving LittleFS to external SPI flash chips (4-8MB) or SD cards to expand storage capacity for logs and web app files. Fast bitbang SPI implementations and increased LittleFS cache sizes were tested to improve performance. The community encourages creating tutorials for these solutions and ongoing firmware improvements to enhance stability and usability of hosting web apps directly on BK7231 devices.
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FAQ

TL;DR: Increasing LittleFS cache from 16 B to 128 B sped up writes by 6×, and “large uploads now work after adding a 5 ms RTOS delay” [Elektroda, p.kaczmarek2, #21589234; #20941452]. Use ≤200 KB partitions, minify .vue files, and firmware ≥1.17.432 for stable on-device WebApp hosting.

Why it matters: you can keep Logs and Filesystem tools available on a closed network without breaking OTA or exhausting heap.

Quick Facts

• Default LittleFS partition: 32 KB (0x8000) [Elektroda, jkwim, post #20928161] • Reliable size on BK7231T/N: 200 KB (0x32000); 256 KB may reboot N chips [Elektroda, Angel0fDeath, post #20931925] • Each file uses whole 4 KB blocks; real usage = ceil(size/4096)×4096 [Elektroda, Angel0fDeath, post #20930090] • Cache 128 B vs 16 B lowers write time by ~6× [Elektroda, p.kaczmarek2, post #21589234] • Heap-low warning appears when LittleFS ≥212 KB on 4 MB flash [Elektroda, jkwim, post #20931820]

1. What is the factory-set LittleFS size and how do I expand it?

OpenBeken ships with a 32 KB LittleFS partition. Enlarge it with lfs_format <bytes>; e.g., lfs_format 0x32000 creates a 200 KB filesystem [Elektroda, jkwim, #20928161; Angel0fDeath, #20930090].

2. Does enlarging LittleFS endanger OTA updates?

LittleFS lives after the application image. If the new size stays below the OTA start address, OTA still works; contents are wiped but firmware installs normally [Elektroda, p.kaczmarek2, post #20928195]

3. Why did my device reboot when uploading a 92 KB file?

Firmware <1.17.432 lacked an RTOS delay in the upload loop, causing watchdog resets during long writes. Update to the delay-patched build or newer and the reboot disappears [Elektroda, p.kaczmarek2, #20941452; Angel0fDeath, #20942411].

4. How do I safely change LittleFS size?

Run lfs_format <newSizeHex>.
Reboot immediately.
Upload files, starting with the largest one first. This prevents stale mounts and spreads blocks efficiently [Elektroda, Angel0fDeath, post #20930090]

5. Which firmware contains the large-upload fix?

Builds ≥1.17.432 (merge ca445c8) include the 5 ms delay; earlier versions need the test RBL from PR #1056 [Elektroda, Angel0fDeath, post #20942411]

6. How much LittleFS space does a file really consume?

LittleFS allocates whole 4 KB blocks, so a 123 B file occupies 4096 B. Formula: used = ((size÷4096)+1)×4096 [Elektroda, Angel0fDeath, post #20930090]

7. Can I host the WebApp (Logs tab only) on the device itself?

Yes. Copy vue.min.js, httpVueLoader.min.js, startup.js, logs.min.vue and indexdevice.html into LittleFS, then point “Configure WebApp” to http://IP/api/lfs/indexdevice.html [Elektroda, jkwim, post #20944917]

8. How do I shrink .vue and .js files to fit 200 KB?

Minify <script> sections with a JS minifier and <style> with a CSS minifier; jkwim cut httpVueLoader from 10.9 KB to 5.8 KB and entire package to 196 KB [Elektroda, jkwim, post #20946139]

9. What happens to LittleFS during OTA?

OTA erases the partition area; keep a tar backup via Web-FS, then restore after flashing [Elektroda, p.kaczmarek2, post #20928195]

10. Why does 256 KB work on BK7231T but fail on BK7231N?

BK7231N’s application+OTA layout leaves less contiguous space; formatting at 0x40000 triggers heap depletion and reboots [Elektroda, Angel0fDeath, #20931925; jkwim, #20931820].

11. What edge case should I watch?

Power-save or any active driver can interrupt large uploads; disable drivers and PowerSave before writing big files [Elektroda, Angel0fDeath, post #20941264]

12. How can I move LittleFS to external SPI flash?

A branch adds software-SPI support; compile with USE_EXT_SPI_LFS in obk_config.h and wire a SOIC-8 NOR flash (e.g., W25Q32) to four GPIOs. Early tests wrote 600 KB successfully albeit slowly [Elektroda, p.kaczmarek2, post #21587455]

13. Is SD-card storage available?

Not yet. SD over SPI is on the roadmap; community interest logged in posts #21587304 and #21587412 [Elektroda, insmod, post #21587304]

14. How do I back up and restore LittleFS quickly?

Use Web-FS “Download TAR”. To restore large sets, upload the biggest files first, then the main tar to avoid heap exhaustion [Elektroda, jkwim, post #20944917]

15. What performance gain will I see from enlarging cache?

Raising LFS cache from 16 B to 128 B cut 600 KB upload time from ~110 s to ~18 s, a 6× speed-up [Elektroda, p.kaczmarek2, post #21589234]

16. The log shows “Low heap warning!”. Safe to ignore?

A single warning appears when LittleFS ≥212 KB on 4 MB flash. If functions run and no resets occur, operation remains stable [Elektroda, jkwim, post #20931820]