Nios® II Embedded Design Suite (EDS)
Support for Embedded Development Tools, Processors (SoCs and Nios® II processor), Embedded Development Suites (EDSs), Boot and Configuration, Operating Systems, C and C++
Intel Support hours are Monday-Fridays, 8am-5pm PST, except Holidays. Thanks to our community members who provide support during our down time or before we get to your questions. We appreciate you!

Need Forum Guidance? Click here
Search our FPGA Knowledge Articles here.
12408 Discussions

Configuration layout of EPCS ?

Honored Contributor I

Hi, this is my first post here ....:oops: 

I would like to understand the layout of the data stored in the EPCS configuration flash. 

I cannot find clear information in the documentation. The doc "Advanced Boot Copier Example" helps because it states that the nios software image (boot record) has following layout: 

4 bytes : length of data 

4 bytes : destination of data 

But what is the format of the fpga hardware configuration ? 

Looking at the EPCS bootloader source code i understand that the first 4 bytes (at the flash address 0x00) are 0x56565656 , the following 4 bytes are not relevant, and the next 4 bytes are the length of the hardware configuration. But reading my EPCS at 0x00 gives: 

0x56565656 0xFFFF0F6C 0xFFFFBFEE 

so 0xFFFFBFEE cannot be the length of the configuration ?!?!?!? 

Also the before mentioned document states that there is a signature "0xa5a5a5a5" which i cannot find anywhere.... 

I simply want to calculate where the hardware configuration ends in the EPCS :( 

Someone can help ? Any documents which explain the layout of the epcs clearly ?
0 Kudos
1 Reply


maybe it helps re-reading epcs eeprom content and analyzing for 'non code' areas or 'pattern filled' areas (on linux).

nios2-flash-programmer '--cable=USB-Blaster on <device description>' --device=<device number> --instance=<device instance to access> --debug -e --go --base=0x<POINTER_TO_EPCS_BASE> -R <epcs-data-backup.file>

objdump -h <epcs-data-backup.file>


partial example (not 'Advanced Boot Copier Example', but custom undefined working bootloader) getting from 'nios2-elf-objdump -s' :


000000 ffffffff ffffffff ffffffff ffffffff  ................
000010 566ffffe 000f1008 00566fff fe000f10  Vo.......Vo.....



or 'cat':






best regards, beyondTime

( nios2eds 13.0sp1, Xenial 16.04 )