User manual

Etherboot User Manual

• Floppy version works but EPROM version doesn’t work. There is a program called rom-scan (Linux,

FreeBSD and DOS versions) in the directory contrib/rom-scan which will help detect problems.

Rom-scan will only work on ISA ROMs though.

• If the EPROM is not detected at all then the contents of the EPROM are not visible to the BIOS.

Check that you have enabled the EPROM with any jumpers or soft conﬁguration settings. Check

that you do not have any conﬂicts in the memory address of the EPROM and any other hardware.

Perhaps you have to prevent it from being mapped out by your BIOS settings. Or perhaps you have

to shadow it with RAM. Maybe you put the code in the wrong half or wrong quarter of the EPROM.

Maybe the access time of the EPROM is not low enough. You can also use the debug program under

BIOS to examine the memory area in question.

• If rom-scan says the EPROM is present but not active, then something prevented the BIOS from

seeing it as a valid extension BIOS. This could be truncation of the EPROM window, maybe you

have a larger EPROM in a slot meant for a smaller one. Maybe there is a checksum error in the

EPROM due to some bits not properly programmed or the EPROM not being fast enough. In one

case that we know of, the 3c503 network card, the ASIC actually returns 2 bytes of 80 80 in the end

locations of the EPROM space. This apparently is a kind of signature. The makerom program in

Etherboot compensates for this, but if the pattern is not 80 80, then the code needs to be modiﬁed.

• If rom-scan says the EPROM is present and active, but BIOS does not see it, then perhaps the

EPROM is located in an area that the BIOS does not scan. The range scanned is supposed to be

0xC0000 to 0xEF800 in increments of 2kB but I have seen some BIOSes that continue the scan into

the 0xF0000 page.

Note that rom-scan will also detect other extension BIOSes mounted on your computer, for example

VGA BIOSes and SCSI adapter BIOSes. This is normal.

For PCI NICs there may be a different reason why the ROM does not work. The PCI IDs of the ROM

must match those of the NIC controller chip or the BIOS will ignore the ROM. The ﬂoppy version

does not undergo this check since it isn’t directly called from the BIOS. You must use the ROM image

with the correct PCI IDs for your NIC.

• Etherboot does not detect card. Are you using the right ROM image? Is the card properly seated in the

computer? Can you see the card with other software? Are there any address conﬂicts with other

hardware? Is the PCI id of the card one that is not known to Etherboot yet? In this case and where you

think there is a bug in Etherboot, please submit a report to the Etherboot-users mailing list.

• Etherboot detects card but hangs computer after detection. Some cards are booby traps while they are

enabled. The typical offenders are NE2000s which will hang the bus if any access is made to the reset

addresses while interrupts are active. You may need to do a hard reset of the computer, i.e. power

down and up again before running Etherboot.

• Etherboot detects card but does nothing after saying Searching for server. Check your network

hardware. Did you select the right hardware interface (AUI, BNC, RJ45)? Is the cabling ok? If you

have a Unix computer on the network and have root privileges, you could run tcpdump or ethereal

looking for broadcast packets on the bootps port. If the requests are getting sent out but no replies are

getting back, check your DHCPD setup. Also check if the server has a route to the client.

• Etherboot obtains IP address but fails to load ﬁle. Check the tftp server. Is the boot image ﬁle

installed? Is the ﬁle world readable? Is the path to the ﬁle allowed by the conﬁguration of tftpd? Is the

client denied by tcpwrapper rules? Did you put the right home directory and ﬁlename in