!!! Arduino nano:

Paste following text at end of:
c:\Users\X\AppData\Local\Arduino15\packages\arduino\hardware\avr\1.6.21\boards.txt

##############################################################

atmega328o.name=Optiboot Nano328
atmega328o.upload.tool=avrdude
atmega328o.upload.protocol=arduino
atmega328o.upload.maximum_size=32256
atmega328o.upload.speed=115200
atmega328o.bootloader.tool=avrdude
atmega328o.bootloader.low_fuses=0xff
atmega328o.bootloader.high_fuses=0xde
atmega328o.bootloader.extended_fuses=0x05
atmega328o.bootloader.path=optiboot
atmega328o.bootloader.file=optiboot/optiboot_atmega328.hex 
atmega328o.bootloader.unlock_bits=0x3F
atmega328o.bootloader.lock_bits=0x0F
atmega328o.build.mcu=atmega328p
atmega328o.build.f_cpu=16000000L
atmega328o.build.board=AVR_ATMEGA328O
atmega328o.build.core=arduino:arduino
atmega328o.build.variant=arduino:eightanaloginputs

############################################################## 

... then reflash bootloader. Then use board as "Optiboot Nano328".