Are that the right ones? If they are different than the other two, you can try to exchange them.
A wrong initrd files can't cooperate well with the imager stick.
I'm not sure if it's supposed to work that way. You can retry with 4 disks inserted and the imager stick.
It seems like I succeeded to recover my NAS !!! ok I'll write down my "adventure" one step by one step :
1, download the package of @maozip, extract it, there are many files and folders, BUT, only the folder " emctools" and "tftpd64.450" are useful for the recovery
2, plug the MAX232 serial, and the LAN cable, set IP adress to 10.4.50.5 on your PC,
3, copy the folder "emctools" to the USB stick which formatted to fat32, the firmware in this folder is "ix4-boot.tgz" and has 107824 Ko
, plug the USB stick to usb port ;
4, run putty by 115200, 8, non, 1, and run "tftpd64.exe" in the folder "tftpd64.45", don't put any others files in it, be cause there are already "zImage (2029 Ko)" and "initrd (2961 Ko)"
5, delete all volumes on the 4 hdd, in Windows or in Linux, whatever, then plug one hdd in the slot 1 (on the bottom),
6, turn on the NAS, interrupt the boot process when you see" press any key to interrupt the autoboot...", tnen we see the prompt, like "marvell>>",
7, run those commands one by one :
setenv initrd_size 0x2f0000
tftpboot 0x2000000 zImage
tftpboot 0x12000000 initrd
nand erase 0x2d4000 0x2f000
nand erase 0xb0000 0x224000
nand write.e 0x12000000 0x2d4000 0x2f0000
nand write.e 0x2000000 0x0b0000 0x224000
8, the NAS will reboot, then we can see the "USB & LAN" icons display on the LCD, then it will create the boot partition on the hdd, when all is finished, the NAS will powered off itself;
9, now we can unplug the USB stick, and plug the LAN cable on your switch,
, we can also unplug the serial cable, but if you want to see the log in putty, you can let it ;
10, now insert the 3 others hdd, and turn on the NAS, wait until the message like, " attention : the volume on disk 1 need overwrite.." when we scroll the display, we can see a IP adress of you LAN,
11, now we can run the "LenovoEMC Storage Manager" on the PC, it will find the NAS, but there is no volume on it, so we should go to option "storage", and create the RAID, this will take very long time, we can see the % on the NAS's LCD screen.
OK, here how I recovered my ix4-200d, thanks to @maozip and @Mijzelf again !!!