Shelly OTA Upgrade 6.4.01/2.3.0/1.5.3 to 6.6.0.18 2_5_2/2.2.2-dev(c0eb301) fails (device not responsive)

[lobocobra]

Bug description

I have around 50 Shelly1 & 2 in use in the house.
=> Shelly1 are on V.6.4.0.1 2_3_0/1.5.3
=> Shelly2 are on V6.5.0.15 2_5_2/2.2.2-dev(c0eb301)

As I wanted to roll-out on all shelly the same firmware and shelly2 obliges to use a dev version, I planned first to upgrade by OTA to: 6.6.0 / 2.5.2 from here : http://thehackbox.org/tasmota/release/020502/

1. first I wanted to upload sonoff-minimal.bin
2. then sonoff.bin to avoid problems with too big code

Step 1 succeeded on the GUI and it gave a success message, but the Shelly 1 and 2 became unreachable (but still pingable).
=> I tried it on 5 different Shelly and ended being forced to uninstall them from the wall, in order to be able to reload the firmware by serial.
I finally ended up after 5hours of testing with 6.6.0.18 //2_5_2/2.2.2-dev(c0eb301)
=> The Shelly work again after erasing them by serial and reflash with VSC.
=> I lost 1 Shelly 1, which became physically damaged (Switch connection has now 230v all time)
=> The other 4 Shelly I could recover.

###I was able to revitalize them by...

1. esptool -cp com10 -ce
2. reload firmware 6.6.0 /2.5.2 (compiled by myself)
   => the 5 are now working on the 6.6.0 firmware but OTA Upgrade did not work.

###Info

• Device used (e.g., Sonoff Basic): shelly 1 & shelly 2
• Tasmota binary firmware version number used: 6.6.0
  • [x ] Pre-compiled
  • [ x] Self-compiled had to complie my version, to make it work
• Flashing tools used: esptool
• Provide the output of command: Backlog Template; Module; GPIO:

'04:32:52 MQT: stat/y_ex_Schocklicht_s2/RESULT = {"NAME":"Shelly 2.5","GPIO":[56,255,17,255,21,83,0,0,6,82,5,22,156],"FLAG":2,"BASE":18}
04:32:52 MQT: stat/y_ex_Schocklicht_s2/RESULT = {"Module":"0 (Shelly 2.5)"}
04:32:52 MQT: stat/y_ex_Schocklicht_s2/RESULT = {"GPIO1":"0 (None)","GPIO3":"0 (None)"}
  Configuration output here:

• Provide the output of this command: Status 0:

`04:34:59 MQT: stat/y_ex_Schocklicht_s2/STATUS = {"Status":{"Module":0,"FriendlyName":["y_ex_Schocklicht_licht","y_ex_Schocklicht_sonos"],"Topic":"y_ex_Schocklicht_s2","ButtonTopic":"0","Power":0,"PowerOnState":3,"LedState":1,"LedMask":"FFFF","SaveData":1,"SaveState":1,"SwitchTopic":"0","SwitchMode":[1,0,0,0,0,0,0,0],"ButtonRetain":0,"SwitchRetain":0,"SensorRetain":0,"PowerRetain":0}}
04:34:59 MQT: stat/y_ex_Schocklicht_s2/STATUS1 = {"StatusPRM":{"Baudrate":115200,"GroupTopic":"sonoffs","OtaUrl":"http://thehackbox.org/tasmota/release/sonoff.bin","RestartReason":"Software/System restart","Uptime":"1T06:38:46","StartupUTC":"2019-10-13T19:56:13","Sleep":50,"CfgHolder":4617,"BootCount":14,"SaveCount":1358,"SaveAddress":"F6000"}}
04:34:59 MQT: stat/y_ex_Schocklicht_s2/STATUS2 = {"StatusFWR":{"Version":"6.5.0.15(sonoff)","BuildDateTime":"2019-06-10T21:47:50","Boot":31,"Core":"2_5_2","SDK":"2.2.2-dev(c0eb301)"}}
04:34:59 MQT: stat/y_ex_Schocklicht_s2/STATUS3 = {"StatusLOG":{"SerialLog":2,"WebLog":2,"SysLog":0,"LogHost":"","LogPort":514,"SSId":["domaincats",""],"TelePeriod":300,"Resolution":"558180C0","SetOption":["00008009","280500000100060000000000000000000000","000000C1"]}}
04:34:59 MQT: stat/y_ex_Schocklicht_s2/STATUS4 = {"StatusMEM":{"ProgramSize":572,"Free":428,"Heap":23,"ProgramFlashSize":2048,"FlashSize":2048,"FlashChipId":"1540EF","FlashMode":3,"Features":["00000809","0FDAE394","041783A1","23B617CC","01003BC0"]}}
04:34:59 MQT: stat/y_ex_Schocklicht_s2/STATUS5 = {"StatusNET":{"Hostname":"y_ex_Schocklicht_s2-0324","IPAddress":"192.168.20.37","Gateway":"192.168.20.2","Subnetmask":"255.255.255.0","DNSServer":"192.168.20.2","Mac":"24:62:AB:00:81:44","Webserver":2,"WifiConfig":5}}
04:34:59 MQT: stat/y_ex_Schocklicht_s2/STATUS6 = {"StatusMQT":{"MqttHost":"192.168.20.90","MqttPort":1883,"MqttClientMask":"DVES_%06X","MqttClient":"DVES_008144","MqttUser":"DVES_USER","MqttCount":376,"MAX_PACKET_SIZE":1000,"KEEPALIVE":30}}
04:34:59 MQT: stat/y_ex_Schocklicht_s2/STATUS7 = {"StatusTIM":{"UTC":"Tue Oct 15 02:34:59 2019","Local":"Tue Oct 15 04:34:59 2019","StartDST":"Sun Mar 31 02:00:00 2019","EndDST":"Sun Oct 27 03:00:00 2019","Timezone":99,"Sunrise":"07:44","Sunset":"18:39"}}
04:34:59 MQT: stat/y_ex_Schocklicht_s2/STATUS9 = {"StatusPTH":{"PowerDelta":0,"PowerLow":0,"PowerHigh":0,"VoltageLow":0,"VoltageHigh":0,"CurrentLow":0,"CurrentHigh":0}}
04:34:59 MQT: stat/y_ex_Schocklicht_s2/STATUS10 = {"StatusSNS":{"Time":"2019-10-15T04:34:59","Switch1":"OFF","Switch2":"OFF","ANALOG":{"Temperature":53.2},"ENERGY":{"TotalStartTime":"2019-06-10T20:49:40","Total":13.633,"Yesterday":0.043,"Today":0.000,"Power":0,"ApparentPower":0,"ReactivePower":0,"Factor":0.00,"Voltage":0,"Current":0.000},"TempUnit":"C"}}
04:34:59 MQT: stat/y_ex_Schocklicht_s2/STATUS11 = {"StatusSTS":{"Time":"2019-10-15T04:34:59","Uptime":"1T06:38:46","SleepMode":"Dynamic","Sleep":50,"LoadAvg":19,"POWER1":"OFF","POWER2":"OFF","Wifi":{"AP":1,"SSId":"domaincats","BSSId":"AC:22:05:85:AD:D3","Channel":11,"RSSI":72,"LinkCount":375,"Downtime":"0T00:13:00"}}}`

TO REPRODUCE

try to upgrade a 6.4+ version to latest 6.6.
=> I assume that before any upgrade a reset 5 needs to be done, then minimal-FW, then 6.6.0. But I stopped my tests, as uninstalling them from the wall took me too long.

[Jason2866]

Core 2.5.2 has a big issue. The memory manager is not stored in iRAM. This can result in problems.
See esp8266/Arduino#6161
Dont use Arduino cores 2.4.x and 2.5.x. Too many unsolved issues (bugs)
Still working without major bugs is core 2.3.0. But this core has security issues
All known (major) issues from core 2.5.2 are fixed in core pre 2.6.

A general point of failure, which can occur on every device, when upgrading:
Fragments left in space in areas Tasmota actually do not use. This fragments are from the original factory firmware. Newer Tasmota versions uses now more space for settings in flash (unused before).
This settings have random values. This can result in not starting (correct) Tasmota after reboot when new firmware is first time active.

To do a safe upgrade:

• Backup your settings
• Do reset 5 all settings will be lost! (except wifi credentials)
• Upgrade
• Restore your settings

This is only neccessary for devices where the flash has never been erased fully ONE time ever

When this precaution actions been followed upgrade will work

[ascillato2]

Closing this issue as it has been answered.

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[lobocobra]

Thanks for the the detailed answer. I downgraded core to 2.3 and did a reset 5 before the firmware upgrade and it worked.

Positive side effect is that the code is 50k smaller and update with a minimal.bin can be omitted. In addition you will have a backup of all config files at the end.