"Step 2: Boot the Poplar board into the u-boot prompt where flashing to eMMC is possible".
This is confusing, since the board is shipped with Android and Fastboot, the described procedure won't work. You will have to do the "recovery" procedure described in "debian_build_instructions.md" in order to install Debian instead of Android.
"Step 2: Boot the Poplar board into the u-boot prompt where flashing to eMMC is possible". This is confusing, since the board is shipped with Android and Fastboot, the described procedure won't work. You will have to do the "recovery" procedure described in "debian_build_instructions.md" in order to install Debian instead of Android.