IMX8MM 4GiB boundary issue

Fabio Estevam festevam at
Thu Feb 24 20:50:49 CET 2022

Hi Tim,

Sorry for resurrecting such an old thread.

On Fri, Sep 25, 2020 at 11:52 AM Tim Harvey <tharvey at> wrote:
> Greetings,
> I'm working with an IMX8MM board that has 4GiB of DRAM. I've found
> that in this configuration the MMC driver and FEC network driver
> appear to have some issues with crossing the 4GiB address space. If I
> tell U-Boot I have 3GiB everything is ok, but when I set it to 4GiB I
> see the following:
> Loading Environment from MMC... Error found for upper 32 bits
> Error found for upper 32 bits
> Error found for upper 32 bits
> *** Warning - No block device, using default environment
> In:    serial
> Out:   serial
> Err:   serial
> Net:   DP83867
> Warning: ethernet at 30be0000 (eth0) using random MAC address - ea:22:3a:4d:8f:d5
> eth0: ethernet at 30be0000 [PRIME]
> Hit any key to stop autoboot:  0
> On the FEC ethernet side I don't see any errors reported but ping's
> fail with 4GiB DRAM.

Yes, just noticed the "Error found for upper 32 bits" and FEC breakage
on an imx8mm iotgate board.

Is there any progress with regards to the support of 4GB of RAM on imx8mm?


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