Wifi Rev2 Upload Issues (verification error;content mismatch)

I am having an issue with uploading sketches/applications that are bigger than around 16KiB to my Arduino Uno Wifi Rev2. I think that the issue is likely related to incorrect mEDBG firmware on the 32u4. I was reprogramming the 32u4 to use it as a HID and then wasn't sure what to reprogram it as to make it work again to program the 4809.

I have tried flashing the 32u4 with `medbg_updi.hex` from Atmel Studio (tools/medbg_fw.zip) and also firmware provided with Xplained Yourself (https://hackaday.io/project/162372/files), whose UPDI .hex file seems the same as what is provided with Atmel Studio. Currently my 32u4s EEPROM has been programmed with the .eep from Xplained Yourself. The original EEPROM has been erased. I have noted that with only 0s in the EEPROM, no programming of the 4809 works at all.

Below I have included an AVRDUDE log including the error (the intended program never seems to run as no Serial communication is detected after programming):
```
avrdude: Version 6.3-20190619
Copyright (c) 2000-2005 Brian Dean, http://www.bdmicro.com/
Copyright (c) 2007-2014 Joerg Wunsch

System wide configuration file is "/home/logan/.arduino15/packages/arduino/tools/avrdude/6.3.0-arduino17/etc/avrdude.conf"
User configuration file is "/home/logan/.avrduderc"
User configuration file does not exist or is not a regular file, skipping

Using Port : usb
Using Programmer : xplainedmini_updi
Overriding Baud Rate : 115200
avrdude: usbdev_open(): Found mEDBG CMSIS-DAP, serno: XYS by Vidmo UPDI/04
avrdude: usbdev_open(): WARNING: failed to set configuration 1: Device or resource busy
avrdude: max packet size expected 512, but found 64 due to EP 0x81's wMaxPacketSize
avrdude: Found CMSIS-DAP compliant device, using EDBG protocol
AVR Part : ATmega4809
Chip Erase delay : 0 us
PAGEL : P00
BS2 : P00
RESET disposition : dedicated
RETRY pulse : SCK
serial program mode : yes
parallel program mode : yes
Timeout : 0
StabDelay : 0
CmdexeDelay : 0
SyncLoops : 0
ByteDelay : 0
PollIndex : 0
PollValue : 0x00
Memory Detail :

Block Poll Page Polled
Memory Type Mode Delay Size Indx Paged Size Size #Pages MinW MaxW ReadBack
----------- ---- ----- ----- ---- ------ ------ ---- ------ ----- ----- ---------
signature 0 0 0 0 no 3 0 0 0 0 0x00 0x00
prodsig 0 0 0 0 no 61 61 0 0 0 0x00 0x00
fuses 0 0 0 0 no 9 0 0 0 0 0x00 0x00
fuse0 0 0 0 0 no 1 0 0 0 0 0x00 0x00
fuse1 0 0 0 0 no 1 0 0 0 0 0x00 0x00
fuse2 0 0 0 0 no 1 0 0 0 0 0x00 0x00
fuse4 0 0 0 0 no 1 0 0 0 0 0x00 0x00
fuse5 0 0 0 0 no 1 0 0 0 0 0x00 0x00
fuse6 0 0 0 0 no 1 0 0 0 0 0x00 0x00
fuse7 0 0 0 0 no 1 0 0 0 0 0x00 0x00
fuse8 0 0 0 0 no 1 0 0 0 0 0x00 0x00
lock 0 0 0 0 no 1 0 0 0 0 0x00 0x00
data 0 0 0 0 no 0 0 0 0 0 0x00 0x00
usersig 0 0 0 0 no 64 64 0 0 0 0x00 0x00
flash 0 0 0 0 no 49152 128 0 0 0 0x00 0x00
eeprom 0 0 0 0 no 256 64 0 0 0 0x00 0x00

Programmer Type : JTAGICE3_UPDI
Description : Atmel AVR XplainedMini in UPDI mode
ICE hardware version: 0
ICE firmware version: 1.13 (rel. 43)
Serial number : XYS by Vidmo UPDI/04
Vtarget : 5.00 V
JTAG clock megaAVR/program: 0 kHz
JTAG clock megaAVR/debug: 0 kHz
JTAG clock Xmega: 0 kHz
PDI clock Xmega : 0 kHz

avrdude: Partial Family_ID returned: "mega"
avrdude: AVR device initialized and ready to accept instructions

Reading | ################################################## | 100% 0.04s

avrdude: Device signature = 0x1e9651 (probably m4809)
avrdude: erasing chip
avrdude: reading input file "/tmp/arduino_build_614042/Scan.ino.hex"
avrdude: writing flash (24244 bytes):

Writing | ################################################## | 100% 7.46s

avrdude: 24244 bytes of flash written
avrdude: verifying flash memory against /tmp/arduino_build_614042/Scan.ino.hex:
avrdude: load data flash data from input file /tmp/arduino_build_614042/Scan.ino.hex:
avrdude: input file /tmp/arduino_build_614042/Scan.ino.hex contains 24244 bytes
avrdude: reading on-chip flash data:

Reading | ################################################## | 100% 6.00s

avrdude: verifying ...
avrdude: verification error, first mismatch at byte 0x0200
0x08 != 0x0c
avrdude: verification error; content mismatch
avrdude: jtag3_edbg_signoff(): unexpected response 0x03, 0x80

avrdude done. Thank you.
```
Is there a way to get the original firmware and a typical EEPROM back? I'm not 100% sure that the firmware is the issue but that is really the only thing I changed (via dfu-programmer). I find it odd that I can program small programs but not ones that are larger (mismatch at 0x200)... I almost wonder if somehow the 32u4 is now programming the wrong part of flash in the 4809 or if some fuse may be out of wack...

Any help reseting/fixing my Uno Wifi Rev2 would be appreciated.

Start with the reported avrdude log and the medbg_updi.hex and .eep files from tools/medbg_fw.zip and Xplained Yourself. Reproduce the ATmega4809 write and verification mismatch at 0x0200, then determine whether the 32u4 firmware or EEPROM state explains it and document a reliable recovery path.

Written by the indexing model from the issue text.