avrdude verification error mismatched content

I'm using the Sparkfun CAN485 board which is a modified Mini (SparkFun AST-CAN485 Dev Board - DEV-14483 - SparkFun Electronics) and the FTDI basic breakout programmer (https://www.sparkfun.com/products/9716) to connect to PC. I have been using the board for a number of months with no issue, and after an upload on wednesday, it no longer allows me to upload code. I am not very savvy with Arduino besides running simple programs.

This is the printout I get from when I try to upload:

Arduino: 1.8.7 (Windows 10), Board: "Can485"

WARNING: Category 'Communications' in library AST_RS485 is not valid. Setting to 'Uncategorized'
Sketch uses 9080 bytes (6%) of program storage space. Maximum is 130048 bytes.
Global variables use 1005 bytes (24%) of dynamic memory, leaving 3091 bytes for local variables. Maximum is 4096 bytes.
C:\Program Files (x86)\Arduino\hardware\tools\avr/bin/avrdude -CC:\Program Files (x86)\Arduino\hardware\tools\avr/etc/avrdude.conf -v -pat90can128 -carduino -PCOM4 -b115200 -D -Uflash:w:C:\Users\bethm\AppData\Local\Temp\arduino_build_967041/main_v9.ino.hex:i

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:\Program Files (x86)\Arduino\hardware\tools\avr/etc/avrdude.conf"

Using Port : COM4
Using Programmer : arduino
Overriding Baud Rate : 115200
AVR Part : AT90CAN128
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 20 8 0 no 4096 8 0 9000 9000 0xff 0xff
flash 65 6 256 0 yes 131072 256 512 4500 4500 0xff 0xff
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 : Arduino
Description : Arduino
Hardware Version: 3
Firmware Version: 6.2
Vtarget : 0.3 V
Varef : 0.3 V
Oscillator : 28.800 kHz
SCK period : 3.3 us

avrdude: AVR device initialized and ready to accept instructions

Reading | ################################################## | 100% 0.00s

avrdude: Device signature = 0x1e9781 (probably c128)
avrdude: reading input file "C:\Users\bethm\AppData\Local\Temp\arduino_build_967041/main_v9.ino.hex"
avrdude: writing flash (9080 bytes):

Writing | ################################################## | 100% 1.73s

avrdude: 9080 bytes of flash written
avrdude: verifying flash memory against C:\Users\bethm\AppData\Local\Temp\arduino_build_967041/main_v9.ino.hex:
avrdude: load data flash data from input file C:\Users\bethm\AppData\Local\Temp\arduino_build_967041/main_v9.ino.hex:
avrdude: input file C:\Users\bethm\AppData\Local\Temp\arduino_build_967041/main_v9.ino.hex contains 9080 bytes
avrdude: reading on-chip flash data:

Reading | ################################################## | 100% 1.90s

avrdude: verifying ...
avrdude: verification error, first mismatch at byte 0x0000
0x14 != 0x0c
avrdude: verification error; content mismatch

avrdude done. Thank you.

the selected serial port
does not exist or your board is not connected

There is currently nothing connected to any pins on the board. I read that it is probably an issue with the bootloader but when I try to re-burn it it says "Error burning bootloader". Any suggestions besides purchasing a new board?

I'm having the exact same issue. Was using the board without problem for several weeks, then all of a sudden noticed that my code wasn't running anymore, and when I went to reprogram it got the following:

avrdude: verification error, first mismatch at byte 0x0000
0x14 != 0x0c
avrdude: verification error; content mismatch
avrdude: verification error; content mismatch

I don't have the tools here to try to reburn the bootloader.

Did you ever resolve your issue?