jmuellers wrote: ↑Fri Mar 22, 2019 2:56 pmHi jamesh, thanks for your answer.
Yeah I've read that section. There's nothing about the slow blinking though, I thought that might yield some additional insight.
If there's something wrong in HW with the SD card interface, I would have imagined the errorcode issued is the one for start.elf, not for the kernel.img. It doesn't seem likely to me that with a defective interface it succeeds to load start.elf and then fails at loading the kernel. Please correct me if that doesn't make sense to you.
Sorry but I don't understand your comment.
Thanks for the explanation. Still leaves the questions:rpdom wrote: ↑Fri Mar 22, 2019 3:59 pmI believe the interface is initially in a reduced mode which just uses one data line. Once bootcode.bin is loaded it switches to the full 4-bit mode and tries to find start.elf. If one or more of the three extra data lines are damaged on the board, or the interface on the Broadcom chip has partially failed, it may be able to get as far as flashing the LED, but no further.
It's not possible to change the PMic unless you really know what you are doing, it's a Bga chip on the board. Is that what you did? The error you are seeing is certainly indicative of a pmic failure.jmuellers wrote: ↑Fri Mar 22, 2019 8:02 pmI've replaced the PMIC since it was broken. Before I did that, I powered all five rails from a lab supply, it behaved exactly the same.
I was under the impression that there are no further regulators on the board, right?
I'll let you know after the weekend if all voltages are as expected, I didn't check yet.
I'll reiterate, the error you are seing is very indicative of a PMIC failure. Not sure if anything else is dead, but the PMIC almost certainly is.jmuellers wrote: ↑Fri Mar 22, 2019 9:05 pmIt's not a BGA, it's a QFN. Soldering QFN (or even BGA) is not a problem for me, it's part of my job
Since I saw the same error when I used a lab supply (I'm fairly positive to have figured out where to apply which voltage), I figure that whatever killed the PMIC in the first place probably took out something else along the way.