@deckingman, I have put a candidate 3.2.1 firmware for the EXP3HC at https://www.dropbox.com/sh/1lwimb98k6hzz3z/AAApVr_P6roUjnya4riDbGAba?dl=0. This fixes the slow startup issue in all but one of the 3HC boards experiencing the issue that it has been tested on. I am hopeful that it will resolve the issue of the extruder running in the wrong direction after power up, even with the delay in config.g reverted to 2 seconds which AFAIR is what you were using before.
@jrockland, you may wish to install this version too, in case the issue you experienced is not solely caused by the faster startup of the MB6HC with firmware 3.2.
@dc42 I managed to get it up to 250mm/s before having a memory crash error ( I should had written it down..) but moving 4 stepper + extruding + sending code to the 2x3hc boards at that speed will create issue for sure... and I was also doing a shape, not a square so the file was heavy.. poor board he is getting worked hard. nothing blew up tho !
reprap is getting better and better, and those 6hg/3hc boards are really solid. we blown multiple motors and heaters core (I remember something crashed IN the board hard enough that the thin metal door bended and shorted the board) and it still running strong.
I tried to delete the post as it look like bang bang was deactivated, so not a firmware issue. anyway probably my bad when I wrote the gcode.
OK so if you have issues with the system not responding to your Gcode or setting changes, and you are using a raspberry pi, MAKE SURE THEIR IS NO MICRO SD IN THE BOARD !!!
They don't say it anywhere, but the provided SD card is NOT to be used if you control it with a raspberry pi.
Sorry you got caught out by that. I've added a note to the Duet 3 page at the top regarding that.