groundFungus:
I have never used the -01 modules, always the -12. I have the reset and GPOI0 connected to push buttons. To put the board in programming mode I hold the GPIO0 button down and press and release the reset button then release the GPIO0 button. Then I compile and upload the program. Neither is held low while programming. I have had very little trouble with uploading.
Yeah, as I would have expected, when you release GPIO0 doesn't seem to make any difference.
By ESP-12, I assume you mean NODEMCU modules? I have zero problems with those.
Regards,
Ray L.