I used "boot0cfg" and destroyed the MBR.All labels dissapear!

BigBrother-{BigB3} bigbrother at bonbon.net
Mon May 2 11:54:20 PDT 2005



Dear,

Please help me with this strange situation, that is due to using boot0cfg 
with wrong switches. I googled it but I did not find any similar case.


On  a working 4.11 freebsd system I wanted to create a floppy bootable 
disk.
This system had one slice and four labels.

I run this command:

boot0cfg -B -o update -s 1 -t 20 fd0


After I run this command I rebooted and I faced a situation where
a) the floppy booting only showed
F1 ???
F2 ???
F3 ???
F4 ???

(whatever I pressed it causes to beep and nothing happens)

b) I removed the floppy disk and booted from the hard disc, but
the same list appeared..and nothing happened.


c) I boot with the 2 kernel/mfsroot diskcs with fixit also and I saw:

fdisk from the 'sysinstall' shows that no slices exist, and all the space 
is unused.

fdisk ad0 shows that there are 4 partitions with information like

======
sysid 32 (uknown)
 	1919950958, 544437093 (265838 Meg) (flag 0x80 active)
 	beggining: cylinder 356 head 97	sector 46
 	end:	   cyllinder 357 head 116 secotr 40

sysid 107 (unknown)
 	....

sysid 83 (unknown)
 	...

sysid 73 (unknown)
 	...
========

Meanwhile I got the message
"slice ad0s1 starts beyong end of the disk: rejecting it"
"slice ad0s2 ......				rejecting it"
"slice ad0s3 ....				rejecting it"
"slice ad0s4 ...				rejecting it"




It seems that all the labels of the single slice have become seperated 
slices.


As a result I cannot mount anything and it seems that all my data is 
inaccessible.



because this is my home freeBSD firewall and I would like to bring it back 
online without reinstalling and setting it up from the beggining (no 
backups sniff:(  ) how can I fix this?

If I recreate partitions (how?) without erasing the file/inode table? how 
can I change the type of every partition to be freebsd? And how can i 
change the slices to be one big slice? I think disklabel can help but I am 
not sure how. How can I save/backup the data on the disk?




Thank you very much in advance!!!


Please if you have any hint of where to search or what to do help me and I 
will post the results (and hopefully the solution)  of this case as a 
reference.


regards,

BB



---
Dreams have no limits!


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