Actually, if you don't know the trick.......
Say you have a perfectly fine booting install on emmc
And then you make a mistake, put in something (SD card) for say a A64 (I have done this)
Opps,, it's dead......even with no SD card in, dead, dead, dead (no leds)
Well, you can (just a guess) take off back, press reset ,, OR
press power, at least 20 seconds,,(then regular 1s press to turn on),, IT'S ALIVE (in frankenstein voice)
FWIW (and BTW, I experiment, have had to do this perhaps 15 times by now)
Please note, bad uboot MUST be removed or disabled
Say you have a perfectly fine booting install on emmc
And then you make a mistake, put in something (SD card) for say a A64 (I have done this)
Opps,, it's dead......even with no SD card in, dead, dead, dead (no leds)
Well, you can (just a guess) take off back, press reset ,, OR
press power, at least 20 seconds,,(then regular 1s press to turn on),, IT'S ALIVE (in frankenstein voice)
FWIW (and BTW, I experiment, have had to do this perhaps 15 times by now)
Please note, bad uboot MUST be removed or disabled