• download SP flash tool for linux (latest release) from https://spflashtool.com/
• download firmware from http://bbs.blackview.hk/viewtopic.php?f=176&t=191529 and unzip
• install libpng12 from deb

untar flash tool and

chmod +x flash_tool*

run

sudo ./flash_tool.sh 

• go to “download section”, select scatter file inside “R*” firmware folder, uncheck “userdata” and press download.
• connect powered down PHONE to USB (yes phone POWERED OFF !!!)
• after green check on screen unplug phone and power on