Remote Upgrade Step by Step plz

Hi,

Its first time for me with altera and the remote upgrade IP. I have a Qsys system that seems to be ok for this type of manipulation. The remote upgrade IP has a 20MHz clk and avalon slave interface connect to nios. Device is a 5CEFA4F23C8 with a N25Q256A13 flash.

For now, I use the same FPGA for factory or application but I use different software for factory or application. Factory soft juste told me "hi" and try to boot on the second FPGA/soft in the flash that just told me "hello". I read "Remote System Upgrade over UART based on Nios II Processor with EPCQ (Cyclone V E FPGA Development Kit)", "Altera Remote Update IP Core User Guide", "AN 603: Active Serial Remote SystemUpgrade Reference Design" and many more. I tried the code of cv_e_rsu_uart project and read a lot of subject into the forum but nothing seem to work for me. The only things i see is

code in factory soft to boot to fpga/soft application

int start_fpga_addr = 0x00260000;

/Set configuration mode to application page

IOWR(REMOTE_UPDATE_0_BASE, 0x4, 1);

printf("step1\r\n");

usleep(1000000);

//Write start address

IOWR(REMOTE_UPDATE_0_BASE, 0x3, start_fpga_addr);

printf("step2\r\n");

usleep(1000000);

//Trigger reconfiguration

IOWR(REMOTE_UPDATE_0_BASE, 0x6, 1);

Do you have a checkpoint list of all the requirement or some hint to be sure all is ok?

Thx for your help