Thanks for your helps. I've set BOOTSEC=0x1000, and made a new install
floppy, but it can't still boot on my IBM TP755CX, the problem it the
same as set BOOTSEC=0x0100. So I have to do more Debug in it. after I
get more procedure, I'll tell yous.

Now I have another problem with a IBM Credit Card Ethernet Adapter.

Here is the Dmesg:

...
pcic0 at isa0 port 0x3f0-0x3f7 irq 6 drq 2
pcic0: controlller 0 (Intel 82365SL Revision 1) has socket A and B
pcmcia0 at pcic0 controller 0 socket 0
pcmcia1 at pcic0 controller 0 socket 1
pcmcia1: CIS checksum failed
pcmcia1: CIS version 2.0 or 2.01
pcmcia1: CIS info: IBM Corp., Ethernet, 0934214, PC-NIC ENCC 990010...
pcmcia1: Manufacture code 0xa4, product 0x2
pcmcia1: function 0: network adapter, ccr addr 20000 mask b
pcmcia1: function 0, config table entry 1: I/O card; irq mask ffff;
iomask 5, iospace 0-1f; mwait_required rdybsy_active wp_active 
bvd_active io16 irqpulse iqrlevel
ne0 at pcmcia1 function 0 port 0x3c0-0x3cf port 0x3d0-0x3df
ne0: IBM CCAE Ethernet
ne0: where did the card go?
....

I've modified if_ne_pcmcia.c(/sys/dev/pcmcia) to add my card's info as

/*
   { "National Semiconductor InfoMover",
     0x00a4, 0x0002, NULL, NULL, 0,
     0x0ff0, { 0x08, 0x00, 0x5a } },
*/
   { "IBM CCAE",
     0x00a4, 0x0002, "IBM Corp.", "Ethernet", 0,
     0x0ff0, { 0x00, 0x04, 0xac } }, 

The "National Semecondution InfoMover" is commented, or the if_ne_pcmcia
will recognize my card as it first (because the same Manufactor code and
productor code), and complain : "0x00,0x04,0xac" should be "0x08,0x00,
0x5a".

>From the dmesg's "ne0: where did the card go?" , I traced the ne2000.c
code(/sys/dev/ic), and found my card failed at:

   tmp = bus_space_read_1(nict, nich, ED_P0_ISR);
   if ((tmp & ED_ISR_RST) != ED_ISR_RST)
      goto out;                            --- it then goto out here.

I know my card is really a ne2000 compatible card. It can be recognized
as a NE2000 Compatible PCMCIA Ethernet card by FreeBSD and OpenBSD.
 
Would you give me more advice now?

Regard
dhongwei