It happened due to my stupidity that I issued command "erase all" in U-boot of WRT160NL router. 
After that there was no more serial console. Only the blue led blinked. 




First idea was to try to restore flash via EJTAG. I soldered LPT connector called Wiggler and used program tjtag3.exe. No connection. 
http://flyrouter.net/doku.php?id=zftlab:technology_jtag

OpenWRT page for WRt160NL says that the only successful way is to use usbjtag but that costs 60 USD.




Next, found an idea to program flash chip directly using SPI protocol. It is simple and works. Finally I dumped flash chip from another WRT160NL router and flashed it. I make available the data that go into flash 
WRT160NL_8MB_flash_dump.zip

Here is a website for flash programmer. It is for another Linksys router model, but it works as the flash chips seem to be standartised: 
http://www.dd-wrt.com/phpBB2/viewtopic.php?p=520266#520266


DB25 # PIN---------------RESISTOR---------------FLASH IC # PIN

7 ----------------------------[150?] ----------------------------- 7
10 ---------------------------[150?]------------------------------ 8
8 ----------------------------[150?]----------------------------- 16
9 ----------------------------[150?]----------------------------- 15
18 ---------------------------------------------------------------- 10 GND (or "GND" on JTAG pads)

|----------- {recommended cable length = 120 mm} ------------|


FLASH IC # PIN--------------------BATTERY ARRAY--------------------FLASH IC # PIN

10 ----------------[ - 1.2 Volt +]----[ - 1.2 Volt +]----[ - 1.2 Volt +]--------------- 2


I used 3.3V power supply. The Vcc pin 2 should not be unsoldered from circuit board. When 3.3V is connected blue LED blinks. If 12 V are connected then can not programm flash chip.



Download software SPIPGMW that works on old XP PC with LPT port, but not via usb-lpt of a notebook. 
http://rayer.ic.cz/programm/programm.htm#SPIPGM



WRT160NL uses two flash chips
old flash chip MX25L6445EMI-10G
new flash winbond 25Q64BVFIG
U-boot works on the both, but for the new flash chip need trunk version of OpenWRT.
 



First tried to download wrt160NL u-boot image file at 
ftp://krumdeel.dyndns.org/Public/wrt160nl/
ftp://krumdeel.dyndns.org/Public/wrt160nl/u-boot-bin/u-boot.bin

Programmed it. The programm complained that file is shorter than flash size. 
Uboot started. I was connected via serial console at 115200.
 

U-Boot 1.1.6 (Nov 16 2009 - 21:16:13)
then came more lines and then it stoped with this line 
"Wait for mfg boot ..."
and it was not responding to ESC from console. 





So I had to go another way. I took apart a working WRT160NL router and dumped flash chip in file WRT160NL_8MB_flash_dump.zipthat I attach as it could be useful for somebody else. And then programmed it to the bricked router. Success!!! U-boot started and I respond to ESC. Since the bricked router had the new flash chip the OpenWRt said Kernel panic, but for this problem I already had a solution described in anoter txt instruction file.