I've just successfully upgraded to 1.02b. I couldn't find definitive instructions for my particular setup so before I forget here they are. I hope someone else gains benefit from them. The only cost was the USBASP which totalled just over £2!

MY SETUP

• QCX 40
• Win10 (32 bit)
• 10 Pin Convert to Standard 6 Pin Adapter Board+USBASP USBISP AVR Programmer USB
  Extreme burner
• Zadig USB driver for above
• Latest QCX firmware

SOURCES
10 Pin Convert to Standard 6 Pin Adapter Board+USBASP USBISP AVR Programmer USB
Extreme burner
Zadig USB driver 
QCX 1.02b Firmware

METHOD
Preparation - PC

• Install Extreme Burner
• There is an extra .xml file in the zip called chips.xml which contains the support for the QCX ATmega328 chip. Copy this file to the program files/extreme burner - AVR/data and overwrite the existing chips.xml file in there
• Open Extreme Burner and select the ATmega328 from the top menu "chip"
• Plug the USBASP into a USB port (I used a USB extension lead so I could easily connect it to the QCX) The USBASP  red LEDs should light up
• Install the Zadig software and install the driver
• Download and extract the QCX firmware .hex file onto your desktop or somewhere you can easily find it, don't load it yet. 

Preparation - QCX

• Power off the QCX
• Expose the 6 way ASP header (if the QCX is in a case), it is situated next to the power connector on the top of the PCB
• Insert the 6 to 10 pin converter onto the header, the 10 way header keyway slot should face into the middle of the PCB
• Carefully connect the ribbon cable between the USBASP  and the 6 to 10 pin converter 

The firmware upgrade

• Power up the QCX
• Firstly, check Extreme Burner is communicating with the ATmega328 chip by pressing the READ ALL Icon in Extreme Burner, this action should successfully download the current contents of the ATmega328 chip
• Now load the QCX firmware .hex file using the OPEN icon in Extreme Burner, you will see all the addresses populate as it loads 
• You should not have adjusted any other parameter in Extreme Burner, the Flash tab should still be displayed
• Press the WRITE ALL icon and wait until Extreme Burner indicates success
• Power off the QCX
• Power on the QCX and 1.02b (or which ever firmware you uploaded) should display during boot - you are done!

Notes

• During Read and Write, Extreme Burner always displayed the message "Incorrect chip found, continue?" which I did. It could be just my setup or ignorance but it did not affect either read or write.
• This was performed on a 32 bit PC. I started on a 64 bit machine but I found that I had to disable a security element regarding unsigned drivers. If you only have a 64 bit machine this is easily done, I just happened to have a 32 bit machine available.

I hope this is of some help to others, this was my first upgrade attempt and frankly very easy indeed.

73s Ted
2E0THH

This is a good guide, Extremeburner is the best program looking at its intuitive interface for avrdude compared to others , thats in imho ofc :)

one essential piece of information to ge the usbasp running under win10 is to get the correct driver installed using zadig, use the lib-usbwin32(v1.2.6.0) driver - se picture

also drop this chips.xml in (unrar first) "C:\Program Files\eXtreme Burner - AVR\Data"  or just ad this to the chips.xml