Hi Victor @Vix
The other test you could do is to rework a 410c board with your 4GB part. The very first batch of prototype 410c boards we built used a 4GB part, but between the SW team and the marketing team we decided that the board really needed an 8GB part to be a general purpose development board. The other deciding factor for 8GB at the time was the price had dropped so that newer generation 8GB parts were less expensive than the 4GB part.
In your case since the 8GB part doesn’t work on your board I would guess the problem is a layout signal integrity problem which is almost impossible to find with an oscilloscope or software. You need to hunt for it in simulation. Look really hard at impedance and cross-talk in the LPDDR signals. Also look at power distribution impedances. Best of luck finding the issue.
Since you will likely need to rework the PCB, what I would strongly recommend is you get the 410c design files from Arrow, leave the core exactly as-is, then change just the peripheral layout for the items you need.
Another option is to work with one of the Qualcomm partners (Intrinsyc, Inforce, eInfoChips etc.) to design a custom board for you. All of them have done custom boards and made their designs work so I am confident they have the necessary skills, and simulation capabilities. Of course they will likely charge you for their efforts.
Depending on your estimated production volumes buying a System on Module (SOM) from one of the partners might be a reasonable solution. The partners can custom build SOMs with 4GB, but a SOM is almost always more expensive than chips on your own board and not a viable solution if your production volumes are high.
-Lawrence-
No longer a Qualcomm employee
Looking for employment.
