Thanks for your advice smoker! I will try to avoid doing anything with the memory for a while. The question I try to find the answer to is why I can mount the memory in my Ubuntu and on my Windows machine but not on my embedded linux system? My task now is to config the linux system and I will make it work to plug in USB drives to it.
I found a description of the FAT boot sector here (
http://www.win.tue.nl/~aeb/linux/fs/fat/fat-1.html). Obviusly in my memory on byte 21 there is value 0xb9 (I have checked with hexdump) which is not a valid media according to FAT specification. The strange thing is that neither my Ubuntu nor my Windows complains about this, but my own homemade Linux kernel does. Does anybody have some ideas why?
Here is the first 512 bytes, i.e. the FAT boot sector, on the USB memory:
----------------------------------------------------
FA 31 C0 8E D8 8E D0 BC 00 7C 89 E6 06 57 8E C0
FB FC BF 00 06
B9 00 01 F3 A5 EA 1F 06 00 00 52
52 B4 41 BB AA 55 31 C9 30 F6 F9 CD 13 72 13 81
FB 55 AA 75 0D D1 E9 73 09 66 C7 06 8D 06 B4 42
EB 15 5A B4 08 CD 13 83 E1 3F 51 0F B6 C6 40 F7
E1 52 50 66 31 C0 66 99 E8 66 00 E8 21 01 4D 69
73 73 69 6E 67 20 6F 70 65 72 61 74 69 6E 67 20
73 79 73 74 65 6D 2E 0D 0A 66 60 66 31 D2 BB 00
7C 66 52 66 50 06 53 6A 01 6A 10 89 E6 66 F7 36
F4 7B C0 E4 06 88 E1 88 C5 92 F6 36 F8 7B 88 C6
08 E1 41 B8 01 02 8A 16 FA 7B CD 13 8D 64 10 66
61 C3 E8 C4 FF BE BE 7D BF BE 07 B9 20 00 F3 A5
C3 66 60 89 E5 BB BE 07 B9 04 00 31 C0 53 51 F6
07 80 74 03 40 89 DE 83 C3 10 E2 F3 48 74 5B 79
39 59 5B 8A 47 04 3C 0F 74 06 24 7F 3C 05 75 22
66 8B 47 08 66 8B 56 14 66 01 D0 66 21 D2 75 03
66 89 C2 E8 AC FF 72 03 E8 B6 FF 66 8B 46 1C E8
A0 FF 83 C3 10 E2 CC 66 61 C3 E8 62 00 4D 75 6C
74 69 70 6C 65 20 61 63 74 69 76 65 20 70 61 72
74 69 74 69 6F 6E 73 2E 0D 0A 66 8B 44 08 66 03
46 1C 66 89 44 08 E8 30 FF 72 13 81 3E FE 7D 55
AA 0F 85 06 FF BC FA 7B 5A 5F 07 FA FF E4 E8 1E
00 4F 70 65 72 61 74 69 6E 67 20 73 79 73 74 65
6D 20 6C 6F 61 64 20 65 72 72 6F 72 2E 0D 0A 5E
AC B4 0E 8A 3E 62 04 B3 07 CD 10 3C 0A 75 F1 CD
18 F4 EB FD 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 FC 4E AE B0 00 00 80 00
02 00 0B FE 7F EA 01 00 00 00 FF 7F 78 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 55 AA
----------------------------------------------------