Hi,
I have redirected this discussion to the ML, because it might be of greater interest.
> Am 15.02.2017 um 11:30 schrieb Matthijs van Duin <matthijsvanduin(a)gmail.com>:
>
> On 15 February 2017 at 10:59, H. Nikolaus Schaller <hns(a)goldelico.com> wrote:
>>>>> Neither have I, but it's easy to detect when ROM is trying to boot through USB since it will conspicuously show up as USB device.
>>>>>
>>>> It could have something to do with the general effect that the USB3 dwc3 does not work
>>>>
>>> But it does! I've used it for USB mass storage mode from u-boot without problems.
>>
>> Oh, ok. This is important info that it works in u-boot. So we just have to look into the kernel.
>
> Except it apparently also doesn't work in the ROM bootloader (on pyra, it does on uEVM).
I have done a quick test:
* console connected
* no SD cards inserted
* battery inserted
* plug in µUSB cable on USB3 port
* powered on (so that BootROM starts searching for an OS)
Result is that my host reports a device called "OMAP5430".
Product-ID: 0xd011
Vendor-ID: 0x0451 (Texas Instruments)
Speed: up to 480 MBit/s
Current (mA): 1000
Interesting is also the last one - they assume that we need a high-current port
for booting over USB...
Anyways, on my unit it seems to respond. What is different to yours? Well, the
VBUS/VBATT fixes are installed. And what we have not verified is if the connector
is soldered equally well.
Then, I am not sure if the BootROM assumes that there is a Palmas chip at all!
Or does it?
If it does, it will likely check the VBUS voltage level to see if USB is plugged in.
In that case we probably have to swap your main board with a fixed one.
A final idea.
Boot order is: leftSD > µSD/eMMC > USB
So if there is something (broken) in eMMC it might not even try USB. That is why pressing
the shoulder button long enough (or permanently) to switch to the empty µSD slot might
be necessary. Boot-ROM seems to try for several seconds until it times out and tries
the next interface. But I have not as much experience with the OMAP5 BootROM as with
the OMAP3 so that I don't know all if its behaviour.
I also tried "ums 0 mmc 1:0" in u-boot but I have not yet cherry-picked all
your patches so this command is missing.
BR,
Nikolaus