default or selected kernelversion does not have config value CONFIG_MTD_UBI_DEBUG_EMULATE_WRITE_FAILURES.
Result is shown for kernelversion 5.4.69

Emulate flash write failures

configname: CONFIG_MTD_UBI_DEBUG_EMULATE_WRITE_FAILURES

Linux Kernel Configuration
└─>Device Drivers
└─>Memory Technology Device (MTD) support
└─>Enable UBI - Unsorted block images
└─>Emulate flash write failures
In linux kernel since version 2.6.24 (release Date: 2008-01-24)  
This option emulates write failures with probability 1/100. Useful for
debugging and testing how UBI handlines errors.