Extremely helpful approach, unfortunately not working here actually

[ameinert]

Frontend: Web (Chrome on win11)
Printer: P15 (labeled "Pristar" but afaik identical to Marklife P15, Marklife Android App working fine)
Steps:

1. OK: Device Discover & Connect seems to work (Frontend OK / Device: blue LED)
2. OK: Design / Templating : Works as expected, great!
3. ISSUE: Print:
   • Start to count to 100% ,
   • at 100% Device powers off (LED off) instantly and in 100% of cases,
   • after ~5 seconds: Frontend responds with 'timeout'

Alternatives:

• Tried to work with precompiled Win x64 cli binary -> Fails to execute, same as issue Windows executable seams not to work #2
• Tried Web Version on Linux: cannot discover printer (Cannot read properties of undefined (reading 'requestDevice'))
  -> maybe my Notebook don´t support BLE or BT-Stack outdated

[tomLadder]

@ameinert Thanks for the report! Helps me a lot to support all the different printers :)

I agree, looks like Pistar and Marklife are the identical printers (just with a different branding), therefore I am surprised it behaves different. Besides the different LED status, does the printer actually print anything?

[tomLadder]

@ameinert I have just released a new version which is available on https://tomladder.github.io/thermoprint/ where i have increased the timeout. Could you please try again and check if it works now?

[tomLadder]

I've added debug logging and a log download option. Could you reproduce the error and attach the downloaded log file to this issue? That would help me investigate further.

[ameinert]

@tomLadder : Many thanks for the follow up on this topic! I just tried with the new version.
Unfortunately no visible change in the behavior except that the application now detects the disconnects instead error message after timeout.
To you initial question: there is no printout , no sound, no paper forward. Just the power off after 100% counter in the frontend.
Log mentions that data is transferred, you will know if power off/disconnect occurs during or after data transfer.
(For the avoidance of doubt: printer is working fine with the Android app ;-))
Debug log is attached. Thanks for spending time into FOSS

thermoprint-debug-2026-04-07T15-13-13.txt

!

[tomLadder]

Thanks for the logs! I've just released a new version, which hopefully fixes the issue 🙃
Could you please test again with your printer and attach me the debug log in case it still does not work

[ameinert]

Tested with the new Version:

• No Change in behavior noticeable (connect ok, print counts to 100%, printer going to off, no printout)
• But Change in debug log

09:08:05.569 [TX] sending 2B in 1 packets, credits=142
09:08:05.571 [TX] sending 4B in 1 packets, credits=141
09:08:05.572 [PRINT] data sent, waiting for result      <--- at this time the frontend shows 100% and printer suddenly changes to "off" 
09:08:08.999 [BLE] unexpected disconnect
09:08:08.999 [PRINT] result: implicit success (disconnect)

thermoprint-debug-2026-04-08T09-08-13.txt

[tomLadder]

Hello @ameinert , finally got time to do another debugging session! Also bought a Pristar P15 to replicate the issue. For me the Marklife P15 and the Pristar P15 (R) behave the same.

I could drastically improve the print speed (same speed as the app now) and improve the overall communication. Can you please test it again and give me feedback if the problem got fixed.

Thanks for the help