Red / red / red blinking error code

Hi all,

My first IotaWatt works great. This second one has been giving us no connectivity for a few months and I’m finally taking time now to troubleshoot it.


  • The device briefly connects to WiFi and gets an IP address, but by the time I go to ping it, it’s gone
  • Within a few minutes throws a red / red / red LED light status code

I’ve connected the USB cable to my Mac, and I’ve opened a program called Serial and started a connection with a Baud Rate of 115200, and I’m able to see output in the terminal as soon as I reconnect it. Here’s the full output:

Ғ"٥name: Iow2
5/31/23 13:11:32 HTTP server started
5/31/23 13:11:36 WiFi connected. SSID=IoT, IP=, channel=11, RSSI -52db
5/31/23 13:11:36 MDNS responder started for hostname Iow2
5/31/23 13:11:36 LLMNR responder started for hostname Iow2
5/31/23 13:11:36 timeSync: service started.

User exception (panic/abort/assert)
                                   --------------- CUT HERE FOR EXCEPTION DECODER ---------------

Panic src/include/DataSource.h:93 const uint8_t* BufferedStreamDataSource<TStream>::get_buffer(size_t) [with TStream = Stream; uint8_t = unsigned char; size_t: Assertion 'cb == stream_rem' failed.


ctx: cont
sp: 3fff2570 end: 3fff27f0 offset: 0000
3fff2570:  3fff5094 00000200 00000238 40239181  
3fff2580:  000000fe 00000000 00000000 00000000  
3fff2590:  00000000 00000000 00000000 4027e64c  
3fff25a0:  3fff1278 ffffffff 3fff4104 000005b4  
3fff25b0:  000005b4 00000000 3fff4104 4022ec0a  
3fff25c0:  007a1200 464ce8e4 00462700 4022ec3e  
3fff25d0:  4010553d 004627e1 3fff1344 4021eeca  
3fff25e0:  3ffeef70 3fff1344 00000001 000005b4  
3fff25f0:  00000000 000005b4 3fff51fc 4021f0a9  
3fff2600:  4022f43d 00000001 00026e62 00026e62  
3fff2610:  00000001 00000001 3fff51fc 4021f16a  
3fff2620:  3fff51fc 3fff2674 00000000 4021f674  
3fff2630:  3fff0760 3fff2650 00026e62 00000000  
3fff2640:  3fff0760 00000001 00026e62 4021ce80  
3fff2650:  65646e00 74682e78 80ff006d 00000001  
3fff2660:  3fff0810 3fff0784 00000020 40100cbf  
3fff2670:  3fff3f54 4023d6a8 00000000 000003e8  
3fff2680:  4023b7dc 3fff40ac 3fff40ec 00000000  
3fff2690:  00000000 3fff0f44 69646500 40220074  
3fff26a0:  80ff26f0 74786574 6d74682f 8900006c  
3fff26b0:  00000000 3fff07a0 3fff26e0 4022d33c  
3fff26c0:  3fff26f0 8000395a 3fff4c00 4023b7dc  
3fff26d0:  4020dfb0 3fff07a0 00000000 4021d1b4  
3fff26e0:  646e692f 682e7865 8a006d74 4023b7c8  
3fff26f0:  6000002f 80fffe22 81100500 00003967  
3fff2700:  00000000 3fff07a0 3fff0760 4023b7d2  
3fff2710:  82450000 3ee622f8 80ff4554 40207d29  
3fff2720:  0042495b 80000000 3fff5400 0000008f  
3fff2730:  80005054 3fff0968 3fff4554 402113c0  
3fff2740:  3fff07a0 3fff0968 3fff4514 00000000  
3fff2750:  00000001 3fff3eb4 3fff0760 00dfe091  
3fff2760:  007a1200 46139d99 00000000 00dfe091  
3fff2770:  00000001 3fff0784 3fff0760 40207dcb  
3fff2780:  3fff2a4c 4021e594 3fff0970 00dfe091  
3fff2790:  00000000 0000020d 3fff0970 4022e4e2  
3fff27a0:  3fff10e8 0000020d 3fff0970 40207f47  
3fff27b0:  3fff4514 00000000 00000001 401001ac  
3fff27c0:  3fffdad0 00000000 3fff11f8 3fff1238  
3fff27d0:  3fffdad0 00000000 3fff11f8 4022e5c4  
3fff27e0:  feefeffe feefeffe 3ffe8604 40100fb9  

--------------- CUT HERE FOR EXCEPTION DECODER ---------------

 ets Jan  8 2013,rst cause:2, boot mode:(3,6)

load 0x4010f000, len 3584, room 16 
tail 0
chksum 0xb0
csum 0xb0

SPI started.

** Restart **

SD initialized.
5/31/23 16:11:43z Real Time Clock is running. Unix time 1685549503 
5/31/23 16:11:43z Reset reason: Software/System restart
5/31/23 16:11:43z Trace:  8:9, 9:3, 9:5, 9:9, 1:2, 1:3, 1:3, 1:1[2], 1:2[3], 9:0[3], 9:0, 9:1, 8:4, 8:6, 8:8, 8:9, 9:3, 9:5, 9:9, 1:2, 1:3, 1:3, 1:1[3], 1:2, 9:0, 9:0, 8:4, 8:2, 8:2, 1:2, 1:3, 10:13
5/31/23 16:11:43z ESP8266 ID: 14634031, RTC PCF8523 (68)
5/31/23 16:11:43z IoTaWatt 5.0, Firmware version 02_07_05
5/31/23 16:11:43z SPIFFS mounted.
5/31/23 13:11:43 Local time zone: -4:00, using DST/BST when in effect.
5/31/23 13:11:43 device name: Iow2
5/31/23 13:11:43 HTTP server started
5/31/23 13:11:43 timeSync: service started.
5/31/23 13:11:46 statService: started.
5/31/23 13:11:46 dataLog: service started.
5/31/23 13:11:46 dataLog: Log file open failed. 2
5/31/23 13:11:46 Program halted.

Based on this forum post, it seems like wiping the SD card might fix it, but @overeasy asked if we could provide more details first, so I figure I’ll leave this here for a bit in case it is helpful.

My next step is I’ll remove the Micro SD card and mount it to look for more information.

Here is a screenshot showing the list of files on the MicroSD card. It’s interesting to me that the modification dates for several of the files are in the distant future. Would that be a cause for its final error: “Log file open failed”?

I’m attaching several of these files here in case they are helpful (renamed to end with .txt so I can upload them)

config-1.txt (1.2 KB)
config.txt (1.2 KB)

iotamsgs.txt (18.3 KB)
iotalog.log.txt (4 KB)
histlog.log.txt (4 KB)

tables.txt (4 KB)

Thank you!

What was your order number?

Order # 127780, November 19, 2022

It’s the SDcard.

I will send a replacement.

Thank you! The solution you outlined in that post (using a tool to reformat the SD card and loading files onto it) sounds straightforward enough so I’m inclined to go ahead and try that unless you’d prefer that I not.

Your call. The replacement is in the mail.

Thank you!