Trying more often does not help, trying a big bunch of different small sticks does.
As soon as you get to immediately seeing the front standby led flickering fast and/or the Droid on the TV you know already it is wrong. Time for the next stick!
Don't ask me why it is so picky specifically about the stick being used for Upgrading/Downgrading Android. Having found one that works it can be repeated with a single try.
Not all media players do it this way. Zidoo emergency recovery for example uses the bootloader to flash a full ROM-image of a working/running player including Android. This in fact clones the total install in one step using mostly the initial factory FW version. There are Pro's and Con's to each method imposed by the SOC supplier being HiSillicon for Egreat and Realtek for Zidoo.