avrdude-slic3r -v -p atmega2560 -c wiring -P COM4 -b 115200 -D -U flash:w:0:C:\Users\kenny\Desktop\3D Print\MK3 Printer Files\Firmware\Firmware-Prusa3d_fw_3_10_0_MK3S\prusa3d_fw_MK3S_3_10_0_4481.hex:i

avrdude-slic3r: Version 6.3-20160220-prusa3d, compiled on Dec 21 2021 at 17:14:48
                Copyright (c) 2000-2005 Brian Dean, http://www.bdmicro.com/
                Copyright (c) 2007-2014 Joerg Wunsch


                Using Port                    : COM4
                Using Programmer              : wiring
                Overriding Baud Rate          : 115200
                AVR Part                      : ATmega2560
                Chip Erase delay              : 9000 us
                PAGEL                         : PD7
                BS2                           : PA0
                RESET disposition             : dedicated
                RETRY pulse                   : SCK
                serial program mode           : yes
                parallel program mode         : yes
                Timeout                       : 200
                StabDelay                     : 100
                CmdexeDelay                   : 25
                SyncLoops                     : 32
                ByteDelay                     : 0
                PollIndex                     : 3
                PollValue                     : 0x53
                Memory Detail                 :

                                         Block Poll               Page                       Polled
                  Memory Type Mode Delay Size  Indx Paged  Size   Size #Pages MinW  MaxW   ReadBack
                  ----------- ---- ----- ----- ---- ------ ------ ---- ------ ----- ----- ---------
                  eeprom        65    10     8    0 no       4096    8      0  9000  9000 0x00 0x00
                  flash         65    10   256    0 yes    262144  256   1024  4500  4500 0x00 0x00
                  lfuse          0     0     0    0 no          1    0      0  9000  9000 0x00 0x00
                  hfuse          0     0     0    0 no          1    0      0  9000  9000 0x00 0x00
                  efuse          0     0     0    0 no          1    0      0  9000  9000 0x00 0x00
                  lock           0     0     0    0 no          1    0      0  9000  9000 0x00 0x00
                  calibration    0     0     0    0 no          1    0      0     0     0 0x00 0x00
                  signature      0     0     0    0 no          3    0      0     0     0 0x00 0x00

                Programmer Type : Wiring
                Description     : Wiring
                Programmer Model: AVRISP
                Hardware Version: 15
                Firmware Version Master : 2.10
                Vtarget         : 0.0 V
                SCK period      : 0.1 us

avrdude-slic3r: AVR device initialized and ready to accept instructions

Reading | ################################################## | 100% 0.01s

avrdude-slic3r: Device signature = 0x1e9801 (probably m2560)
avrdude-slic3r: safemode: hfuse reads as D0
avrdude-slic3r: safemode: efuse reads as FD
avrdude-slic3r: reading input file "C:\Users\kenny\Desktop\3D Print\MK3 Printer Files\Firmware\Firmware-Prusa3d_fw_3_10_0_MK3S\prusa3d_fw_MK3S_3_10_0_4481.hex"
avrdude-slic3r: writing flash (250948 bytes):

Writing | ################################################## | 100% 45.02s

avrdude-slic3r: 250948 bytes of flash written
avrdude-slic3r: verifying flash memory against C:\Users\kenny\Desktop\3D Print\MK3 Printer Files\Firmware\Firmware-Prusa3d_fw_3_10_0_MK3S\prusa3d_fw_MK3S_3_10_0_4481.hex:
avrdude-slic3r: load data flash data from input file C:\Users\kenny\Desktop\3D Print\MK3 Printer Files\Firmware\Firmware-Prusa3d_fw_3_10_0_MK3S\prusa3d_fw_MK3S_3_10_0_4481.hex:
avrdude-slic3r: input file C:\Users\kenny\Desktop\3D Print\MK3 Printer Files\Firmware\Firmware-Prusa3d_fw_3_10_0_MK3S\prusa3d_fw_MK3S_3_10_0_4481.hex contains 250948 bytes
avrdude-slic3r: reading on-chip flash data:

Reading | ################################################## | 100% 32.15s

avrdude-slic3r: verifying ...
avrdude-slic3r: 250948 bytes of flash verified

avrdude-slic3r: safemode: hfuse reads as D0
avrdude-slic3r: safemode: efuse reads as FD
avrdude-slic3r: safemode: Fuses OK (E:FD, H:D0, L:FF)

avrdude-slic3r done.  Thank you.

avrdude-slic3r -v -p atmega2560 -c arduino -P COM4 -b 115200 -D -u -U flash:w:1:C:\Users\kenny\Desktop\3D Print\MK3 Printer Files\Firmware\Firmware-Prusa3d_fw_3_10_0_MK3S\prusa3d_fw_MK3S_3_10_0_4481.hex:i

avrdude-slic3r: Version 6.3-20160220-prusa3d, compiled on Dec 21 2021 at 17:14:48
                Copyright (c) 2000-2005 Brian Dean, http://www.bdmicro.com/
                Copyright (c) 2007-2014 Joerg Wunsch


                Using Port                    : COM4
                Using Programmer              : arduino
                Overriding Baud Rate          : 115200
avrdude-slic3r: prusa_init_external_flash(): MK3 printer did not boot up on time or serial communication failed
avrdude-slic3r: arduino_open(): Failed to initialize MK3 external flash programming mode
avrdude-slic3r: Could not open port: COM4

avrdude-slic3r done.  Thank you.