EZ Flash Junior GBC issues ("Micro SD initial error!")

I've seen a few threads about this, but it's been a while since they've been updated. Here's what's happening, and what I've tried to fix it.

When I boot up my GameBoy Color, "EZ-FLASH" is displayed, then "LOADING...", and finally "Micro SD initial error!" My GameBoy has model no. "CGB-001" written on the back. I have also tried with my GameBoy Advance SP, model no. "AGS-001", with the same results.

I have tried:

• Three different microSD cards - two SanDisk 8G, and one SanDisk...

EZ Flash Junior GBC issues ("Micro SD initial error!")