I'm currently working on a custom board with an IMX28 and everything worked perfectly until now.
I have recently noticed some boot issues on a few percentage of boards ( 10-20 % ) .
I first have suspected an SD issue ( the Bootloader and the Linux are in a SDcard) but after verification the SD0_Power doesn't allow supply to the SDcard when the problem appears.
So the problem is before...
I looked at my Bootmode resistors and i saw that the VDDIO given by the IMX28 is only 1,95V. VDDA and VDDD are correct.
This problem is not constant on these boards which often boot correctly.But when it appears, this happens 4-5 times in a row.
When the processor boots correctly, VDDIO is 3,45V.
I have a few components powered by VDDIO but the global consumption is not really high so I don't get where the problem is.
I power the I.MX28 with a 4,2V power supply on DCDCBATT.
If someone has already seen this problem, I'd be happy to have some informations.