I have jsnL21 C432 4/64 version

I upgraded my phone by 3 button method from 8.2 to Using Firmware Finder, I found a newer version of my firmware in which has a lot of improvement and battery optimization. I want to flash it on my device. I downloaded the firmware but it has 2 files:

  1. Update.zip 2.24GB
  2. Update_full_jsn_l21_hw_eu.zip 643MB

I know I should extract update.app into dload folder but the problem is I have 2 zips and inside of each files has a separated Update.app. How to upgrade with these files?

Firmware Finder

  • You you are talking about third party apps and software like "firmware finder" you should provide a link to the software. Please edit your question and update it with this information.
    – Robert
    Jun 3, 2019 at 17:11
  • yeah sure i did that
    – Amin
    Jun 3, 2019 at 18:39
  • Have you read and act on the "Important notice" in the app description?: Before do anything with your phone i request you, read XDA or 4PDA threads about your phone and how install firmwares or go to telegram chat and give your question.
    – Robert
    Jun 4, 2019 at 7:32
  • yeah i read that but its nothing there :| about 2 files its just a instruction to do it with 1 file
    – Amin
    Jun 4, 2019 at 7:36

1 Answer 1


You must use both files to update your device. First use Update.zip which is the full firmware image, then Update_full_jsn_l21_hw_eu.zip which is the data file.

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