I just got my e3d-v6lite installed (bowden setup), and so far it's great!  I did use an AVRTinyISP to load the firmware... I also couldn't get the bootloader to work.

Well done! I strongly suspect that the bootloader hasn't been installed in the early Presses. I ordered a programmer. Just waiting for it to arrive now. Takes a minimum of a week to get here.

v6 and Lite use the same thermistor, so no worries mixing hex files.

OK, thanks for letting me know. I've compiled the firmware anyway now, just can't get it onto the board. Bootloader just does not want to play. I'd guess it has to be a driver issue, but I just can't get anywhere with that. Even downloaded the 64 bit signed ones to try on the Windows 7 PC, and get exactly the same message. Think I'll just put all this back on the shelf for now and order a programmer. I'm getting nowhere fast with the bootloader.

So firmware is done, but you guessed it. I just cannot get the bootloader to work. I tried FLIP and BootloaderHID. All the same problem. The board is powered (2 green LEDs) and the jumper is set. I tried shorting the reset pins to try and force it to work, but nothing.

I have tried on a Mac, a Windows 7 PC, a Windows XP PC and a Windows Vista PC. All the same result. Bootloader says "Waiting for Teensylu... Hint: press reset" and Flip just says that could not open USB device.

I've got an irritating feeling that the only answer here is "buy a programmer".

Wardjr: I will have to check once I get home, but from memory I'm pretty sure the motherboard was set as type 81.

I had a bit of (limited) success this morning after a little more tinkering before work, so I'll take another look this afternoon. I think (not sure) that the download was somehow corrupted. I'll redownload the original firmware from Solidoodle later and start again from scratch with it. Fingers crossed.

I thought before I did the hardware install, I'd look at flashing the firmware. I've got the board into boot mode, hooked up to my Mac. I'm running Arduino 1.6.4 with Teensyduino installed. I've set my board to "Teensy++ 2.0".

I thought I would keep it simple first by using a known quantity before starting to mess around, so I tried to compile the unmodded SD firmware. I get a load of warning messages, mainly centering on defined variables which are not used, most of which relate to thermal runaway protection. Gets past all that, then just stops at around 60% (the blue progress bar is just past halfway). It says it's compiling, but nothing is happening. It gets to that point within about 10-20 seconds, but then just sits there and goes no further. It doesn't crash or give an error, the progress bar just stops moving.

As I said, this is the unmodified SD Press firmware that I am trying to compile, so it should just work. But it doesn't. Any ideas anyone?

All I am trying to do is set the thermistor to type 5 and I wanted to set the max temp to 245 as well. But I'm failing dismally!

I ordered a V6-Lite. 

From reading the installation guide: The thermistor value needs to be changed, and they also recommended changing PID_MAX to 150.  I believe that is to reduce the chance of "overshooting" the maximum temperature.  The V6-Lite has a max temperature of 245c, so lowering the Max temperature would be recommended (the press default is 300).

Don't adjust PID_MAX. there is no need for this, as PID auto tuning will reduce the amount of overshoot substantially. In my experience too low of a PID_MAX creates oscillation in temperature even with proper PID auto tuning.

Newer V6s and Lite6s ship with a 20w (edit: 25w) heater cartridge also, which doesn't overshoot as aggressively.

From reading the installation guide: The thermistor value needs to be changed, and they also recommended changing PID_MAX to 150.  I believe that is to reduce the chance of "overshooting" the maximum temperature.  The V6-Lite has a max temperature of 245c, so lowering the Max temperature would be recommended (the press default is 300).