Checking sdram contents after verify error when downloading

Hello,

I have written my own sdram-controller which addresses a sdram with the memory-range from 0x04000000 - 0x04ffffff.
I have an original sdram-controller generated by the NIOS II software which addresses a sdram with the memory-range from 0x02000000 - 0x02ffffff.
Both controllers are connected to the NIOS II processor programmed in the FPGA.
When I run my program in the memory-range from 0x02000000 - 0x02ffffff everything works file.
Simple testing then the sdram with the memory range from 0x04000000 - 0x04ffffff gives no errors.
When I try to run my program in the memory-range from 0x04000000 - 0x04ffffff I got a verifying error when loading it into the sdram.
Is there a way to check what has been loaded into the sdram from memory-locations 0x04000000 - 0x04ffffff.
I tried to use nios2-download but there are no options to read data from sdram-locations. I think it can only download data to sdram.
Does somebody have some idea how I could check the contents of the sdram.

Regards,

WMO