Here is some experience, I use them to locate where the VoCore broken, if you have a power supply show VoCore current, this might help.

1. input 5V, current first 0.12A then go 0.15A then 0.25A … your VoCore is normal to boot. When it is in uboot, the current consume is 0.12A~0.14A, and once it into linux, the current is about 0.15A, when wifi prepare to start, the current rise to 0.25A~0.30A(note, the power mush stable or it will reboot at this point), then the current will stable at 0.18A~0.19A if you do not transfer much data through wifi.

2. input 5V, current keep 0.12A~0.14A, can not boot … there is high chance flash is damaged. flash current consume is about 0.03~0.05A average.

3. input 5V, current keep 0.06~0.12A, can not boot … this might be memory problem.

4. input 5V, current is about 0.01A ~ 0.05A, can not boot … this should be RT5350 problem, might be BGA part is not well connect to pad. This always happened if you iron temperature is too high and the weight of the chip will make some BGA balls drop from pads. This should be rare to happen, but from my test, almost every time I use high temperature iron will cause such problem.

5. input 5V, current > 0.5A, I think your power supply is short connected somewhere.

6. input 5V, current = 0A, of course, the power is not connected, or chip is totally destroyed.