Flash of arduino nano not being updated when trying to burn bootloader

Hello,

After I had problems uploading sketches to my arduino nanos, I decided to burn a new bootloader to them. I don't have an USBasp laying around so I used my arduino UNO as ISP. After uploading the code and connecting all wires, I tried to burn the bootloader to one of my nanos:

avrdude: Version 6.3-20171130
         Copyright (c) 2000-2005 Brian Dean, http://www.bdmicro.com/
         Copyright (c) 2007-2014 Joerg Wunsch

         System wide configuration file is "C:\Users\Bram\AppData\Local\Arduino15\packages\arduino\tools\avrdude\6.3.0-arduino14/etc/avrdude.conf"

         Using Port                    : COM3
         Using Programmer              : arduino
         Overriding Baud Rate          : 19200
avrdude: stk500_getsync() attempt 1 of 10: not in sync: resp=0x15
avrdude: stk500_getsync() attempt 2 of 10: not in sync: resp=0x15
Fout bij het branden van de bootloader.
         AVR Part                      : ATmega328P
         Chip Erase delay              : 9000 us
         PAGEL                         : PD7
         BS2                           : PC2
         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    20     4    0 no       1024    4      0  3600  3600 0xff 0xff
           flash         65     6   128    0 yes     32768  128    256  4500  4500 0xff 0xff
           lfuse          0     0     0    0 no          1    0      0  4500  4500 0x00 0x00
           hfuse          0     0     0    0 no          1    0      0  4500  4500 0x00 0x00
           efuse          0     0     0    0 no          1    0      0  4500  4500 0x00 0x00
           lock           0     0     0    0 no          1    0      0  4500  4500 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 : Arduino
         Description     : Arduino

avrdude: stk500_getparm(): (a) protocol error, expect=0x14, resp=0x14

avrdude: stk500_getparm(): (a) protocol error, expect=0x14, resp=0x02

avrdude: stk500_getparm(): (a) protocol error, expect=0x14, resp=0x10
         Hardware Version: 4744608
         Firmware Version: 0.4611299
         Topcard         : STK502
         Vtarget         : 1.8 V
         Varef           : 0.0 V
         Oscillator      : Off
         SCK period      : 0.1 us

avrdude: stk500_initialize(): (b) protocol error, expect=0x10, resp=0x01
avrdude: initialization failed, rc=-1
         Double check connections and try again, or use -F to override
         this check.

avrdude: stk500_disable(): protocol error, expect=0x14, resp=0x10

avrdude done.  Thank you.

Avrdude doesn't seem to get in sync with my nano. I tried running Nick Gammons board programmer:

Atmega chip programmer.
Written by Nick Gammon.
Version 1.38
Compiled on Oct 22 2018 at 12:40:42 with Arduino IDE 20000.
Attempting to enter ICSP programming mode ...
Entered programming mode OK.
Signature = 0x1E 0x95 0x0F 
Processor = ATmega328P
Flash memory size = 32768 bytes.
LFuse = 0xFF 
HFuse = 0xDA 
EFuse = 0xFD 
Lock byte = 0xFF 
Clock calibration = 0xA9 
Type 'L' to use Lilypad (8 MHz) loader, or 'U' for Uno (16 MHz) loader ...
Using Uno Optiboot 16 MHz loader.
Bootloader address = 0x7E00
Bootloader length = 512 bytes.
Type 'Q' to quit, 'V' to verify, or 'G' to program the chip with the bootloader ...
Erasing chip ...
Writing bootloader ...
Committing page starting at 0x7E00
Committing page starting at 0x7E80
Committing page starting at 0x7F00
Committing page starting at 0x7F80
Written.
Verifying ...
Verification error at address 7E00. Got: 0xFF  Expected: 0x11 
Verification error at address 7E01. Got: 0xFF  Expected: 0x24 
Verification error at address 7E02. Got: 0xFF  Expected: 0x84 

etc, etc....


496 verification error(s).
First 100 shown.
Programming mode off.
Type 'C' when ready to continue with another chip ...

It looks like the flash memory of the nano isn't being updated.
I also ran Nick Gammons board detector to check the bootloader:

Atmega chip detector.
Written by Nick Gammon.
Version 1.20
Compiled on Oct 22 2018 at 12:45:39 with Arduino IDE 20000.
Attempting to enter ICSP programming mode ...
Entered programming mode OK.
Signature = 0x1E 0x95 0x0F 
Processor = ATmega328P
Flash memory size = 32768 bytes.
LFuse = 0xFF 
HFuse = 0xDA 
EFuse = 0xFD 
Lock byte = 0xFF 
Clock calibration = 0xA9 
Bootloader in use: Yes
EEPROM preserved through erase: No
Watchdog timer always on: No
Bootloader is 2048 bytes starting at 7800

Bootloader:

7800: 0xFF 0xFF 0xFF 0xFF 0xFF 0xFF 0xFF 0xFF 0xFF 0xFF 0xFF 0xFF 0xFF 0xFF 0xFF 0xFF 
7810: 0xFF 0xFF 0xFF 0xFF 0xFF 0xFF 0xFF 0xFF 0xFF 0xFF 0xFF 0xFF 0xFF 0xFF 0xFF 0xFF 

.......

7FF0: 0xFF 0xFF 0xFF 0xFF 0xFF 0xFF 0xFF 0xFF 0xFF 0xFF 0xFF 0xFF 0xFF 0xFF 0xFF 0xFF 

MD5 sum of bootloader = 0xE0 0xDE 0xEB 0xD3 0xC3 0xF5 0x60 0x21 0x2A 0xF1 0x7C 0x68 0xB9 0x34 0x4B 0xAE 
No bootloader (all 0xFF)

First 256 bytes of program memory:

00: 0xFF 0xFF 0xFF 0xFF 0xFF 0xFF 0xFF 0xFF 0xFF 0xFF 0xFF 0xFF 0xFF 0xFF 0xFF 0xFF 

........

F0: 0xFF 0xFF 0xFF 0xFF 0xFF 0xFF 0xFF 0xFF 0xFF 0xFF 0xFF 0xFF 0xFF 0xFF 0xFF 0xFF 

Programming mode off.

Does anyone know what is going on? Have I bricked my nanos?

Thanks for the help.