1. Get factory raw image of mmcblk0p28 partition: https://coderus.openrepos.net/jollarecovery/jolla-factory.tar.xz https://coderus.openrepos.net/HASHSUM.html
2. Format micro SD card to ext4 or btrfs, extract raw image from archive and copy it yo card. Rename file to jolla.img
3. Boot in recovery mode, enter shell
4. Execute:
    mount /dev/mmcblk1p1 /mnt
    dd if=/mnt/jolla.img of=/dev/mmcblk0p28
5. Wait until image will be copied to partition, no output will be produced.
6. Execute after copying complete:
    sync
    reboot
7. Phone will be rebooted and should start working again
8. In case if wifi networking won't work you need to do a factory reset after booting your phone.
.. In case if wifi networking still won't work you need to reinstall kernel-adaptation-sbj using mobile network, or download this file and install locally: https://coderus.openrepos.net/jollarecovery/kernel-adaptation-sbj-3.4.91.20140612.1-10.22.1.jolla.armv7hl.rpm