Optionally, you can insert the memory card back onto the mainboard, and connect your eReader to an external power source in order to test the replacement EPD panel for any artefacts and/or dead pixels.

This process of testing EPD panels without connecting the battery, frontlight, touch, and/or pen input (depending on model) is basically the same process used by suppliers of new-old-stock EPD panels in China, when they sell them on online stores like AliExpress and/or eBay, which you would've most likely purchased your display panel from.

However, they would sometimes test displays on another device that uses the same display or used a display with similar specifications, in order to not have too many test devices around, for example, a Kobo Aura display tested using a Kindle Paperwhite 2, or a Likebook Mars display tested using a Dangdang Reader R7.

At this stage, you should not have the infrared light guide attached to the panel but not to the mid-frame, which is what the photo shows as I made mistakes while writing this guide, so that you don't have to.

You should instead have the display panel loosely attached to the mid-frame, without the infrared light guide and front bezel attached at this stage.

Connect a USB cable from a USB power adaptor or external battery to your eReader, and it should automatically power on.

Without the infrared light guide, you will not be able to navigate menus on your eReader and open a book or Pocket article, but you will still be able to use the power button to take it in and out of sleep mode, and power off.

Don't mind the weird selection of books in the middle row, but I had not removed the previous owner's sideloaded e-books before carrying out this repair.