FAQ
TL;DR: Devs cut OpenBeken W800 firmware 44 % (966 kB → 543 kB) while chasing W806 support; “900 kB vs 90 kB seems like a huge difference” [Elektroda, p.kaczmarek2, post #21081741] Wi-Fi remains stable on old SDK but drops to –79 dBm on the new stack [Elektroda, insmod, post #21526615]
Why it matters: fitting inside 1 MB flash decides whether W806 boards can run OTA-capable builds at all.
Quick Facts
• Flash size: W800/W801 2 MB; W806 1 MB [Elektroda, divadiow, post #21081609]
• Typical full OBK image: 950-976 kB; slim image: 543 kB [Elektroda, divadiow, post #21387419]
• Heap on new SDK: ~88 kB free, stack 100 kB [Elektroda, insmod, post #21526615]
• Wi-Fi RSSI: –71 to –89 dBm (old SDK); often –79 dBm (new SDK) [Elektroda, max4elektroda, post #21530706]
• OTA method: local HTTP server; Web-App OTA not in W800 branch [Elektroda, p.kaczmarek2, post #21081517]
What are the main hardware differences between W800/W801 and W806?
W800 and W801 integrate Wi-Fi, Bluetooth and 2 MB QSPI flash, whereas W806 ships with 1 MB flash and no factory-calibrated RF front-end. The silicon still contains dormant Wi-Fi cores, but missing calibration blobs block radio use [Elektroda, divadiow, post #21081609] [Elektroda, divadiow, post #21386566]
Why did the first W806 flash attempts fail with a CAN/NAK error?
The flasher aborted after packet 57 of 957 because the image exceeded the 1 MB address space; the tool replied “CAN” when no acknowledgment arrived [Elektroda, divadiow, post #21081609]
How small must the firmware be to fit W806?
RA-formatted images must stay below roughly 980 kB including headers, leaving space for EasyFlash vars. The current slim build ships at 543 kB, providing ~450 kB margin [Elektroda, divadiow, post #21387419]
Which compile-time switches helped cut image size?
Disabling MQTT TLS, internal NTP, Tasmota JSON emulation, AT-command hostif, and the SDK web server removed ~400 kB from .fls output [Elektroda, p.kaczmarek2, post #21386515] [Elektroda, insmod, post #21534154]
Does the new v1.00.10 SDK improve RAM usage?
Yes. Replacing minilibc with newlib and switching FreeRTOS to heap_5 yields 88 kB free heap versus ~29 kB before, a 203 % increase [Elektroda, insmod, post #21526615]
What downside was observed after the SDK upgrade?
Wi-Fi sensitivity worsened; several users report long connection times and packet loss at RSSI below –79 dBm, making OTA unreliable [Elektroda, insmod, post #21526615] [Elektroda, max4elektroda, post #21530706]
Is UART logging affected by the size-optimised build?
Early newlib builds lost TX0 output because printf stubs were trimmed. Restoring minilibc_port.c from SDK v1.00.10 re-enabled logs without growing flash size noticeably [Elektroda, p.kaczmarek2, post #21525698]
Can I back up factory Tuya firmware on a W800 board?
Yes. Use the Python script from post #21542722 to read the flash over UART at 921 600 bps, then save the .fls file. Tuya partitions remain encrypted [Elektroda, divadiow, post #21542912]
Edge-case: what happens if config saves during power loss?
Interrupting a flash-write corrupts the fixed-address config sector; the device reboots in AP mode with default settings [Elektroda, p.kaczmarek2, post #21525689]
How do EasyFlash variables differ from the old fixed sector?
EasyFlash stores key-value pairs in a wear-levelled pool from 0x1B000, allowing dynamic size, multiple SSIDs and frequent flash-vars writes without sector-erase fatigue [Elektroda, insmod, post #21526615]
Quick 3-step OTA update on W800 boards?
- Compile or download .ota image under 980 kB.
- Upload via local HTTP server at /upload in the Web GUI.
- Reboot; check UART for “Boot complete” message within 5 s [Elektroda, p.kaczmarek2, post #21525681]
Which statistic shows the benefit of stripping features?
File size dropped by 423 kB, a 44 % reduction, when optional services were disabled (966 kB → 543 kB) [Elektroda, divadiow, post #21387419]
Can W806 ever get full Wi-Fi support?
Experts doubt it: “You won’t make it work… there is no factory calibration data” [Elektroda, GitHub comment quoted in #21386566]. Until calibration values and RO flash access emerge, W806 remains a UART-only target.
