Dell N2048 ERROR: can't get kernel image

Hi , I have old witch model Dell N2048.connected with console to switch and then I did :

Display boot menu > Restore configuration to factory default

it was ok but after that i did by mistake : reformat partition or something like that and then now i stuck on U-Boot.

When I connect to the switch with a console I get the following message:

U-Boot SPL 2012.10-00078-g24e99ea (Jun 24 2014 - 16:41:18)
BENCH SCREENING TEST1
=========================================
IPROC_XGPLL_CTRL_3: 0x15400000
IPROC_XGPLL_STATUS: 0x8000021e
DCO code: 33
PASS
=========================================
HWRev: 0x95 AVS: 0x1 VOUT Init: 0x64 VOUT Set: 0x5f Steps: 5 Fail: 0
DEV ID= 0000dc14
SKU ID = 0x0
DDR type: DDR3
MEMC 0 DDR speed = 800MHz
ddr_init2: Calling soc_ddr40_set_shmoo_dram_config
ddr_init2: Calling soc_ddr40_phy_calibrate
C01. Check Power Up Reset_Bar
C02. Config and Release PLL from reset
C03. Poll PLL Lock
C04. Calibrate ZQ (ddr40_phy_calib_zq)
C05. DDR PHY VTT On (Virtual VTT setup) DISABLE all Virtual VTT
C06. DDR40_PHY_DDR3_MISC
C07. VDL Calibration
C07.1
C07.2
C07.4
C07.4.1
C07.4.4
VDL calibration result: 0x30000003 (cal_steps = 0)
C07.4.5
C07.4.6
C07.5
C08. DDR40_PHY_DDR3_MISC : Start DDR40_PHY_RDLY_ODT....
C09. Start ddr40_phy_autoidle_on (MEM_SYS_PARAM_PHY_AUTO_IDLE) ....
C10. Wait for Phy Ready
Programming controller register
ddr_init2: Calling soc_ddr40_shmoo_ctl
Validate Shmoo parameters stored in flash ..... OK
Press Ctrl-C to run Shmoo ..... skipped
Restoring Shmoo parameters from flash ..... done
Running simple memory test ..... OK
DDR Tune Completed
 Micron MT29F2G08ABAEA, 128 KiB blocks, 2 KiB pages, 16B OOB, 8-bit
NAND:   chipsize 256 MiB


U-Boot 2012.10-00078-g24e99ea (Jun 24 2014 - 16:41:18)

DRAM:  1 GiB
WARNING: Caches not enabled

NAND:   Micron MT29F2G08ABAEA, 128 KiB blocks, 2 KiB pages, 16B OOB, 8-bit
NAND:   chipsize 256 MiB
In:    serial
Out:   serial
Err:   serial
arm_clk=1000MHz, axi_clk=499MHz, apb_clk=124MHz, arm_periph_clk=500MHz
Net:   Registering eth
Broadcom BCM IPROC Ethernet driver 0.1
Using GMAC0 (0x18022000)
et0: ethHw_chipAttach: Chip ID: 0xdc14; phyaddr: 0x1
serdes_reset_core pbyaddr(0x1) id2(0xf)
bcmiproc_eth-0
boot in 3 s
Creating 1 MTD partitions on "nand0":
0x000000200000-0x00000f000000 : "mtd=4"
/image1 not found!
ubifsload - load file from an UBIFS filesystem

Usage:
ubifsload   [bytes]
    - load file 'filename' to address 'addr'
Wrong Image Format for bootm command
ERROR: can't get kernel image!
Saving Environment to NAND...
Erasing Nand...
Erasing at 0x160000 -- 100% complete.
Writing to Nand... done
/image2 not found!
ubifsload - load file from an UBIFS filesystem

Usage:
ubifsload   [bytes]
    - load file 'filename' to address 'addr'
Wrong Image Format for bootm command
ERROR: can't get kernel image!

I downloaded firmware N2000Stdv6.7.0.4.stk and installed on my PC  Tftp server. honestly i don't know how to run it and communicate between my PC and switch ( if needed to solve my isusue)

i tried to config with:

setenv ipaddr 10.0.0.50 ( switch ip? connected between switch port1 to my router)
setenv server 10.0.0.10 ( My PC IP and also TFTP server)
saveenv

no ping between my pc and switch..

printenv:

active=image2
backup=image1
baudrate=9600
boot_image1=ubifsload 0x70000000 /image1; bootm 0x70000074
boot_image2=ubifsload 0x70000000 /image2; bootm 0x70000074
bootargs=console=ttyS0,9600 maxcpus=2 mem=1024M root=/dev/ram mtdparts=nand_iproc.0:1024k(nboot),512k(nenv),256k(vpd),256k(shmoo),243712k(fs),16384k(diags) ubi.mtd=fs ethaddr=28:f1:0e:f0:49:29 quiet
bootcmd=run fpboot; if test $active = $i1; then run ubifscfg; run boot_image1;setenv active image2; saveenv; run boot_image2;else; if test $active = $i2; then run ubifscfg; run boot_image2;setenv active image1; saveenv; run boot_image1;fi; fi; if test $active = $mfg; then run mfgdiags;fi;
bootdelay=3
bootfile=uImage
ethact=bcmiproc_eth-0
ethaddr=28:f1:0e:f0:49:29
fpboot=setenv bootargs console=ttyS0,${baudrate} maxcpus=2 mem=1024M root=/dev/ram ${mtdparts} ubi.mtd=fs ethaddr=$ethaddr quiet
i1=image1
i2=image2
ipaddr=10.0.0.50
ipaddress=10.0.0.50
loadaddr=0x70000000
mfg=mfg
mfgdiags=echo running diags to program MAC address; nand read 0x61007fc0 0x0f000000 0xf80000; bootm 0x61007fc0; setenv active image1
mtddevname=nboot
mtddevnum=0
mtdids=nand0=nand_iproc.0
mtdparts=mtdparts=nand_iproc.0:1024k(nboot),512k(nenv),256k(vpd),256k(shmoo),243712k(fs),16384k(diags)
netmask=255.255.255.0
partition=nand0,0
serverip=10.0.0.10
stderr=serial
stdin=serial
stdout=serial
ubifscfg=ubi part nand0,4 0x0; ubifsmount fs
ver=U-Boot 2012.10-00078-g24e99ea (Jun 24 2014 - 16:41:18)

Environment size: 1498/65532 bytes

Please help me fix the problem and reinstall firmware via u-boot (or whatever is needed to solve the problem)
Thank you!