Flashing 6.2.1

[Mike Robertson]

I am having great difficulty flashing several Sonoff devices at a version greater than 5.14.0.  It works sometimes but not always.  I have tried flashing through the serial port and OTA.  When flashing OTA I always flash minimal first and then 6.2.1.  Typically at the end the LED flashes on and off with a 1s interval.  This is supposed to mean the flash failed.

Flashing 5.14.0 through serial works every time.  I haven't tried it OTA. 

The devices I have tried on are T1 UK (3ch and 2ch), Touch and Basic (early version and R2).  They all behave exactly the same.

I feel I must be missing something since I don't see anybody else reporting a similar problem.

Any suggestions?

[Greg from Oz]

Are you sure the LED flashing is not just that it cannot connect to the mqtt broker? That happens to me sometimes.

What do you see if you connect via serial and monitor what is being output?

I have upgraded from 5.14 to 6.21 OTA with no problems.

I use tasmoadmin to upgrade. It's great for doing upgrades.

[Phil]

Is this perhaps a consequence of the CFG_HOLDER count?  as someone used to a quick edit and compile to personalise each devices installation i recently fell foul of the protection offered by the CFG_HOLDER property in the user_config.h file.   the resulting symptoms are a flashing of the devices led post install, and if you can hook up and catch serial output (might be @ 9600 baud not the usual 115200) you will witness an endless reboot cycle with attempts to connect to wifi without credentials and a 30 second attempt to set up an AP before rebooting and repeating.

the fix can be found in the wiki but essentially involves changing the CFG_HOLDER value compiling and flashing before resetting it to the original value and again compiling and reflashing, and once done a usual ota upgrade should again be successful.

[Mike Robertson]

I thought I could just reply to the email notification.  Apparently not, so here it is again...

Sometimes there are messages appearing on the serial link and sometimes not.  I don’t remember it ever failing to connect to the MQTT server.  Sometimes it couldn’t connect the AP which didn’t makes sense since sometimes it did.  Obviously, I don’t know what’s happening when I try to upgrade by OTA.

[Mike Robertson]

That sounds promising.  The symptoms you describe are very similar to what I'd found.  I have had the effect when using OTA from the 'maddox' URL but that could be because of earlier settings.  I'll give this a try and see what happens.

Update:  I think you've hit the nail on the head.  I created a minimal and a standard binary build.   The minimal had a changed CFG_HOLDER.  I then OTA flashed 3 devices, first minimal and then standard and the all worked without error.

Thanks for your help.  My confidence is restored.

[Phil]

Glad to hear its sorted, my own route to a solution was slow as i didnt use the correct google term to search, after about a week i finally looked up 'tasmota / endless boot cycle'  which finally led me to the wiki entry.

Im still not sure how I fell into the trap either which is still bugging me..  

And Since, I now commission new devices 1 at a time flashing the precompiled binaries and configuring via the web gui and commands issued through tasmoadmin.