Antes de comenzar con la actualización es necesario realizar una pequeña modificación en la placa DVmega, instalar un puente entre un pin del conector y un contacto del condensador C45.

Una vez hecho el puente es recomendable volver a conectar la placa a la Raspberry y comprobar que todo funciona correctamente. Si todo arranca con normalidad podemos pasar a la actualización en sí.
Para ejecutar la actualización es necesario conectarse mediante ssh a la Raspberry, para ello podemos utilizar Putty. Una vez conectados lo primero que debemos hacer es poner el sistema de archivos en modo lectura-escritura:
pi-star@pi-star:~$ rpi-rw
Nos movemos al directorio temporal
pi-star@pi-star(rw):~$ cd /tmp
Descargamos las herramientas necesarias para la actualización.
pi-star@pi-star(rw):tmp$ wget http://www.pistar.uk/downloads/dvmega-flash-tools.zip
--2020-01-25 00:41:00-- http://www.pistar.uk/downloads/dvmega-flash-tools.zip
Resolving www.pistar.uk (www.pistar.uk)... 104.27.185.136, 104.27.184.136, 2606:4700:3035::681b:b988, ...
Connecting to www.pistar.uk (www.pistar.uk)|104.27.185.136|:80... connected.
HTTP request sent, awaiting response... 200 OK
Length: 954 [application/zip]
Saving to: dvmega-flash-tools.zip
dvmega-flash-tools. 0%[ ] 0 --.-KB/s
dvmega-flash-tools. 100%[=====================>] 954 --.-KB/s in 0s
2020-01-25 00:41:00 (24.6 MB/s) - dvmega-flash-tools.zip saved [954/954]
Descargamos el firmware, en este caso la versión 3.26
pi-star@pi-star(rw):tmp$ wget http://www.dvmega.auria.nl/images/DVMEGA_RH_V326_UNO.zip
--2020-01-25 00:43:52-- http://www.dvmega.auria.nl/images/DVMEGA_RH_V326_UNO.zip
Resolving www.dvmega.auria.nl (www.dvmega.auria.nl)... 185.27.142.205
Connecting to www.dvmega.auria.nl (www.dvmega.auria.nl)|185.27.142.205|:80... connected.
HTTP request sent, awaiting response... 200 OK
Length: 50117 (49K) [application/zip]
Saving to: DVMEGA_RH_V326_UNO.zip
DVMEGA_RH_V326_UNO. 0%[ ] 0 --.-KB/s
DVMEGA_RH_V326_UNO. 100%[=====================>] 48.94K 267KB/s in 0.2s
2020-01-25 00:43:56 (267 KB/s) - DVMEGA_RH_V326_UNO.zip saved [50117/50117]
Descomprimimos los archivos de herramientas y firmware en el directorio dvmega.
pi-star@pi-star(rw):tmp$ unzip -d dvmega dvmegaunzip -d dvmega dvmega-flash-tools.zip
Archive: dvmega-flash-tools.zip
inflating: dvmega/flash_gpio.sh
inflating: dvmega/flash_usb.sh
pi-star@pi-star(rw):tmp$ unzip -j -d dvmega DVMEGA_RH_V319_UNO.zip_UNO.zip_UNO.zip2_UNO.zip6_UNO.zip
Archive: DVMEGA_RH_V326_UNO.zip
inflating: dvmega/Changelog.txt
inflating: dvmega/DVMEGA_RH_V326_UNO.hex
inflating: dvmega/DVMEGA_RH_V326_UNO_JAPAN.hex
No movemos al directorio dvmega y comprobamos que estan todos los ficheros necesarios, herramientas y la nueva version de firmware.
pi-star@pi-star(rw):tmp$ cd dvmega/
pi-star@pi-star(rw):dvmega$ ls
Changelog.txt DVMEGA_RH_V326_UNO_JAPAN.hex flash_usb.sh
DVMEGA_RH_V326_UNO.hex flash_gpio.sh
Comprobamos que el fichero comprimido incluye la versión para Japón, que no necesitamos, y la eliminamos.
pi-star@pi-star(rw):dvmega$ rm dDVMEGA_RH_V326_UNO_JAPAN.hex
A continuación ejecutamos la actualización.
pi-star@pi-star(rw):dvmega$ sudo ./flash_gpio.sh
Warning: Stopping pistar-watchdog.service, but it can still be activated by:
pistar-watchdog.timer
Warning: Stopping dstarrepeater.service, but it can still be activated by:
dstarrepeater.timer
Found DVMEGA_RH_V326_UNO.hex firmware...
avrdude-original: Version 6.1, compiled on Jul 7 2015 at 10:29:47
Copyright (c) 2000-2005 Brian Dean, http://www.bdmicro.com/
Copyright (c) 2007-2014 Joerg Wunsch
System wide configuration file is "/etc/avrdude.conf"
User configuration file is "/root/.avrduderc"
User configuration file does not exist or is not a regular file, skipping
Using Port : /dev/ttyAMA0
Using Programmer : arduino
Overriding Baud Rate : 115200
avrdude-original: Using autoreset DTR on GPIO Pin 7
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
Hardware Version: 3
Firmware Version: 4.4
Vtarget : 0.3 V
Varef : 0.3 V
Oscillator : 28.800 kHz
SCK period : 3.3 us
avrdude-original: AVR device initialized and ready to accept instructions
Reading | | 0% 0.00s
Reading | ################################################## | 100% 0.00s
avrdude-original: Device signature = 0x1e950f
avrdude-original: safemode: lfuse reads as 0
avrdude-original: safemode: hfuse reads as 0
avrdude-original: safemode: efuse reads as 0
avrdude-original: NOTE: "flash" memory has been specified, an erase cycle will be performed
To disable this feature, specify the -D option.
avrdude-original: erasing chip
avrdude-original: reading input file "DVMEGA_RH_V326_UNO.hex"
avrdude-original: input file DVMEGA_RH_V326_UNO.hex auto detected as Intel Hex
avrdude-original: writing flash (29546 bytes):
Writing | | 0% 0.00s
Writing | ################################################## | 100% 4.18s
avrdude-original: 29546 bytes of flash written
avrdude-original: verifying flash memory against DVMEGA_RH_V326_UNO.hex:
avrdude-original: load data flash data from input file DVMEGA_RH_V326_UNO.hex:
avrdude-original: input file DVMEGA_RH_V326_UNO.hex auto detected as Intel Hex
avrdude-original: input file DVMEGA_RH_V326_UNO.hex contains 29546 bytes
avrdude-original: reading on-chip flash data:
Reading | | 0% 0.00s
Reading | ################################################## | 100% 3.12s
avrdude-original: verifying ...
avrdude-original: 29546 bytes of flash verified
avrdude-original: safemode: lfuse reads as 0
avrdude-original: safemode: hfuse reads as 0
avrdude-original: safemode: efuse reads as 0
avrdude-original: safemode: Fuses OK (E:00, H:00, L:00)
strace: |autoreset: Broken pipe
strace: |autoreset: Broken pipe
strace: |autoreset: Broken pipe
strace: |autoreset: Broken pipe
strace: |autoreset: Broken pipe
avrdude-original done. Thank you.
strace: |autoreset: Broken pipe
Once flashing has been completed, you should reboot your Pi-Star
Finalizada la actualización, reiniciamos la Raspberry.
pi-star@pi-star(rw):dvmega$ sudo reboot
Broadcast message from pi-star@pi-star on pts/0 (Sat 2020-01-25 00:47:07 CET):
The system is going down for reboot NOW!
Comprobamos que se ha cargado correctamente la nueva versión.

Ya solo queda disfrutar de la radio!