The engraver attachment requires version 2.2.1 or newer of the Eggbot extensions for Inkscape, but does not require a firmware update.
[We actually recommend sticking with the original EBB firmware version for the time being– that’s the version that we install, and that is for good reasons. A new version of the firmware (that is fully backwards compatible with the Inkscape driver) is near completion, but there may be minor issues here and there with the currently-posted newer firmware versions.]
Now, there are two separate issues that you’ve described.
First, with the EBB that won’t enter bootloader mode: It may be the case that one of your buttons is not working correctly. Try plotting with the Eggbot as you normally would (but perhaps without any pen). While it is drawing, try pressing the RST button to reboot the EBB. It should lose communication, and give you an error message saying so. Then, while plotting again, try pressing the PRG button. It should *pause* the plot, and give you a message saying that it has done so.
Second, for the engraver that isn’t working:
Make sure that you’ve enabled the engraver under the Options tab of EggBot Control, and make sure to test it (turning the pot from one side to the other) *while* you are plotting something with the EggBot. Check your wiring, make sure that the metal part of the motor wire leads (not just the insulation) is making contact with the screw terminals. Make sure that the servo cable is attached with the correct colors on both sides. Check the assembly: Make sure that the diode and transistor orientations are correct. Be sure that when you added the LED, the long lead was going into the square hole.
