To create fix firmware reset for Samsung  SCX-4300 printers
need to know serial number (SN)   and   firmware version

The firmware version can be found by printing Configuration report
MENU – REPORT –SYSTEM DATA- OK
Serial Number can be found also on the label back of the printer

If the printer NOT allows you to print the page (or the cartridge is at  0%) quickly type
the following key combination to print reports in TECH MODE
MENU – COPIES  – <(stanga)  – >(dreapta)  – MENU  –  >(dreapta)   ecranul afiseaza Ready Tech
MENU COPY– SYSTEM DATA

After reset is  necessary only refill toner cartridge
Video refill, disassembly, cleaning cartridge MLT-D1092
https://www.ereset.com/refill/reincarcare-refill-cartus-mlt-1092-scx-4300/