As the title says: Originally, the U disk GRUB was made to use bootlace.com --floppy --chs 0x00 to write GRUB into the MBR of the U disk. Now I want to use the U disk to boot into DOS, how to clear the GRUB in the U disk MBR?
China DOS Union
Union site: www.cn-dos.net Forum site: www.cn-dos.net/forum
DOS stands for freedom, openness and progress. Let us work hard, learn from the openness and GNU spirit of FreeDOS and Linux, and together build and grow a free GNU GPL world!
中国DOS联盟论坛 » GRUB4DOS、SYSLINUX及其它启动管理软件讨论专区 » [Help] Please, Master Budian: How to clear the GRUB in the U盘 MBR?
View 2,088 Replies 2
Original Poster
Posted 2008-05-23 12:42 · 中国 贵州 遵义 电信
Floor 2
Posted 2008-05-23 13:30 · 中国 河南 南阳 电信
银牌会员
★★★★
不甘寂寞的人
Credits 2,491
Posts 1,115
Joined 2003-09-24 00:00
22-year member
UID 10292
Gender Male
Posts 1,115
Joined 2003-09-24 00:00
22-year member
UID 10292
Gender Male
Status Offline
Install the DOS boot code to the USB drive using the sys command, which will overwrite the GRUB boot code.
First, you boot the USB drive to GRUB, then execute in GRUB:
chainloader (fd0)/io.sys
boot
Then you enter DOS. In DOS, execute sys A: where A: is your USB drive.
Of course, you need to ensure that the DOS system files io.sys, msdos.sys, command.com, and the sys command itself are already on the USB drive.
Since the USB drive is recognized as a floppy disk by your BIOS, your USB drive has no MBR (even if there is an MBR, it is not visible under DOS), and there is only a FAT boot sector. The DOS boot sector you install using the sys command is on the first sector of the FAT. The GRUB boot sector is also on the first sector of the FAT.
First, you boot the USB drive to GRUB, then execute in GRUB:
chainloader (fd0)/io.sys
boot
Then you enter DOS. In DOS, execute sys A: where A: is your USB drive.
Of course, you need to ensure that the DOS system files io.sys, msdos.sys, command.com, and the sys command itself are already on the USB drive.
Since the USB drive is recognized as a floppy disk by your BIOS, your USB drive has no MBR (even if there is an MBR, it is not visible under DOS), and there is only a FAT boot sector. The DOS boot sector you install using the sys command is on the first sector of the FAT. The GRUB boot sector is also on the first sector of the FAT.
因为我们亲手创建，这个世界更加美丽。
Floor 3
Posted 2008-05-23 15:26 · 中国 贵州 遵义 电信
Originally posted by ysyzygz at 2008-5-23 12:42 PM:
As the title: Originally, I used bootlace.com --floppy --chs 0x00 to write GRUB into the MBR of the USB flash drive to make the USB flash drive GRUB bootable. Now I want to boot into DOS from the USB flash drive, how to clear GRUB in the MBR of the USB flash drive?
Thanks to Master Budian.
Forum Jump: