FAQ
TL;DR: LN882H modules flash like ESP8266: ground BOOT, talk UART, upload OpenBeken. A full 2 MB backup takes 14 min (~19 kB/s) at 115 200 baud [Elektroda, divadiow, post #21378212] “All my work is based on reverse engineering” [Elektroda, stefanmandl1, post #21376767] Why it matters: clean backups and stable Wi-Fi save hours of rework.
Quick Facts
• Supply rail: 3.3 V ± 5 % required; ≥200 mA recommended [Elektroda, niterian, post #21443865]
• Default boot baud: 921 600 bps (TX1/B9) [Elektroda, divadiow, post #21593199]
• Typical flash: 16 Mbit (2 MB) addressable 0x000000–0x1FFFFF [Elektroda, divadiow, post #21378212]
• Backup speed Windows tool: ~9 min 50 s at 921 600 baud [Elektroda, divadiow, post #21381159]
• OpenBeken current release: v1.18.110 (June 2025) [Elektroda, @GUTEK@, post #21581324]
Which pins do I need for flashing an on-board LN882HKI?
Use A9 (BOOT, pull low), A3 (RX0), A2 (TX0), B9 (UART-log TX1), 3.3 V and GND. Keep BOOT low during reset, then release after the loader connects [Elektroda, divadiow, post #21593199]
How do I create a verified backup before flashing?
- Connect UART and pull BOOT low. 2. Run LN882Loader dumpFlash 0x0 0x1FFFFF to save dump.bin. 3. Compare CRC32 of dump with a second read; mismatches indicate wiring noise [Elektroda, divadiow, post #21378212]
Why does my Windows GUI flasher stop after a few hundred bytes?
Several FTDI232 adapters leave TX floating; swap to an isolated CH340G board or enable proper drive strength. This fixed read failures for multiple users [Elektroda, niterian, post #21443865]
What causes watchdog reboots in GPIO Doctor on LN882H?
Pins A13–B2 are wired to internal QSPI; forcing them to output crashes RAM. New firmware blocks these pins to prevent WDT resets [Elektroda, p.kaczmarek2, post #21447718]
Is power-save mode safe to enable?
Usually yes, but poor 3.3 V rails or crowded 2.4 GHz channels can drop the link. Test with PowerSave 0, then 1. Wi-Fi stack lives inside the vendor SDK, not OpenBeken [Elektroda, p.kaczmarek2, post #21579867]
My switch disconnects minutes after boot. What else can I try?
• Add a 100 nF ceramic across VCC-GND near the module. • Disable Quick Connect for noisy routers. • Check router logs for deauth frames. One user solved drops by shielding from a PV inverter EMI source [Elektroda, @GUTEK@, post #21579876]
Can I use higher dump speeds than 115 200 baud?
Yes. changeBaudrate(921600) in LN882Loader cuts 2 MB dump time to ≈9 min 50 s, though actual throughput stays below the theoretical line rate [Elektroda, divadiow, post #21381159]
Where is the OpenBeken configuration stored in flash?
From offset 0x1EB000 a plain-text block starting with “CFG” holds JSON settings; it appears after first boot and will differ from factory Tuya data [Elektroda, p.kaczmarek2, post #21456320]
Does flashing erase RF calibration?
The GUI flasher overwrites only the application area; RF-cal at 0x1FC000 remains. A full-chip erase may delete it, degrading range [Elektroda, p.kaczmarek2, post #21579867]
Any edge-case that bricks the chip?
Feeding 5 V UART signals without a level shifter burns the RX0 pad; the module then boots but never accepts commands—confirmed in two repair cases [“LN882H repair notes”, 2025].
How do I compile OpenBeken for LN882H myself?
Install LLVM-ARM-None-Eabi 9+, clone OpenBK7231T_App, run make platform=LN882H. Enable optional SSDP or IGMP in lwipopts.h, then flash the produced bin via UART [Elektroda, p.kaczmarek2, post #21430384]
Is there a GUI dumper for Windows now?
Yes. LN822H_dump_tool wraps LN882H_CMD_Tool.exe and shows progress ticks while preserving full backup capability [Elektroda, spleefer90, post #21564936]
