[SOLVED] SD card MBR interpretation issue

Hello,

Issue: MBR pointing to Empty sector as Relative/Boot sector.

I am interfacing SD card on ARM: LPC3250.On issuing READ_SINGLE_BLOCK(CMD17) command i am getting MBR output as below.
data[0] = 0x00000000
.....
data[110] = 0x00000000
data[111] = 0x02000000
data[112] = 0x3D06000A
data[113] = 0x0087BDFD
data[114] = 0xEF790000
data[115] = 0x0000003A
data[116] = 0x00000000
..........
data[127] = 0xAA550000

As per the other post and document-> I need to examine the partition tables located at offset 0x01BE in this sector and relative sector number at 0x1C6. attached snap below


I am Interpreting above output i.e 0x00000087*512 = 0x10E00. (Relative/Boot sector address) as per SDCardmap.pdf attached below.

But when i open my 2GB SD card in Hex Editor Neo MBR is not visible, i am seeing BOOT sector at address 0x0000 attached snap below


and @address 0x10E00 all the bytes are 0 snap below


1) why MBR is not visible in Hex Editor Neo?
2) Why MBR pointing to 0x10E00 location but boot sector start at location 0x0000 ?
3) I am using example code of LPC3250 initialize and read command sequence looks fine.

I tried both SDFormatter tool and Windows format Default/Fat16/Fat32, 4 different 2GB SD card of Transcend. Please help where am i missing I am stuck :bang:.

I do not know about the hex editor Neo, but all of the hex editors that I have used do not allow you to see the MBR. The method I use to see the MBR is to create an ISO file of the disk I wish to view and use a hex editor on that.
Tip I use the free HxD hex editor as I have found it to be the best one available.

Thanks for the replay pjmelect.

When i connect SD card by card reader it will detected as drive not disc. Is it possible to convert drive to ISO file? any software?
I tried HXD hex editor but same result(Drive not ISO file).

Yes it is possible to convert a drive (SD card) to an ISO, I used disc as a generic term to describe storage media. I use Ultra ISO to create the ISO file of a "drive" but I think that most ISO programs allow you to do this. I think that Ultra ISO gives you a free months trial to try it out.

try ' mkiso' a commandline utility for creating iso file from disk.

@pjmelect

Yes you are right image file gives MBR and Boot sector properly attached snap below
MBR

BootSector @0x10e00(0x00000087*0x200)


But when the Drive opened directly.NO MBR, Boot sector at address 0x00000(1st block).
MBR

BootSector @0x10e00(0x00000087*0x200)


Code reading MBR properly as per ISO file. How to fix this?
I tried SD Card Formatter tool- SD Association and windows formatting, is there any better sd card format tool?

Could you explain in more detail what the problem is now, you cannot read the MBR sectors of a drive with any (that I know of) hex editor program, they all start at the boot sector of the first partition. It is easy to confuse the two sectors with a hex editor program as they look similar. The only way I know of to see or edit the MBR (please tell me if anyone knows another way) is to create a ISO or image of the drive.
What is wrong with the Windows formatting?

Problem solved: Yes i was confused with Hex editor.
as u said ISO Is right view of MBR(0x0000) and Bootsector(Relative address 0x00000087).

Thanks pjmelect & srizbf for ur time and kind replay.