Editing BIOS for USB boot on the old MB

[Raider]

Hello.
I have old motheboard lucky star kta 133 pro with award bios.
I want to edit it's BIOS because I want to boot it from USB. MB haven't built-in network card, but it may boot from LAN.
cbrom showed a parts list of my BIOS:

Code Select Expand

No. Item-Name         Original-Size   Compressed-Size Original-File-Name
  0. System BIOS       20000h(128.00K)  12EBEh(75.69K)  TEST.BIN
  1. XGROUP CODE       08BD0h(34.95K)   05EA7h(23.66K)  awardext.rom
  2. ACPI table        02448h(9.07K)    00E61h(3.59K)   ACPITBL.BIN
  3. EPA LOGO          0168Ch(5.64K)    002AAh(0.67K)   AwardBmp.bmp
  4. YGROUP ROM        02B00h(10.75K)   01DC1h(7.44K)   awardeyt.rom
  5. GROUP ROM[ 0]     01C00h(7.00K)    00DA4h(3.41K)   _EN_CODE.BIN
  6. OEM0 CODE         08000h(32.00K)   027E4h(9.97K)   d:\bios\addrom\VIAFM.617
Here is no any LAN boot rom.
Please, say, what I may to do with this? Maybe, I can simply add plpbt.rom in BIOS, not replace? Or what ROM  I must replace with?

[vesalocal]

Usually your network interface card has a socket for additional boot-ROM. 
If activated, it will be called from your BIOS at a specified address.
So you have to add plop to your NIC ROM.

To add plop to your BIOS there is no general recipe...  To give you an idea
on BIOS editing take a look at http://rayer.ic.cz/romos/romose.htm

Good luck!

[Raider]

vesalocal, big thanks for this advice! Also link is very useful 
My MB have 1 ISA slot, so I just added ROM to BIOS with help of CBROM as ISA ROM. It's working!!! But not as I want. It writes

Option ROM: press D to disable boot manager

, then

Boot manager initialized, PNP BIOS used

and it's all. No menus, no other actions.
I tried to set option "force int" when I compile rom from bin -

forceINT: This forces the boot manager to hook the INT 19h/INT 18h. If you have a PNP bios, then the boot manager does not use the PNP bios feature of the boot device sequence. The boot manager will be started before any boot devices is tried (when INT 19h mode is used) or the boot manager is the last program that is started when all boot devices failed to boot (when INT 18h mode is used).

I thought that this option will allow me to boot from usb earlier then other devices will be tried. But plop also don't boot from any device or show menus. It write

Boot manager initialized, hooked INT19h

, and it's again all 
What do plop must show when it loaded as a part of BIOS?
PS. My English isn't very well, sorry for this.

[Raider]

Au, have you any ideas?
Possibly, ROM was compiled as PCI ROM, and it must be recompiled as ISA rom for good working?

[huyunqq]

try :
1.plpbtrom -forceINT plpbtrom.bin plpbt-i.rom
  use  bromcfg change plpbt-i.rom to isa rom.
  added ROM to BIOS with help of CBROM as isa ROM

2.one rtl8135 nic (or mod plpbtrom.bin)
  added ROM to BIOS with help of CBROM as PCI ROM
  configure the bios first boot from lan.