Andre, I read all the other thread under your message. I didn't understand what are you trying to do. If this can help, I can say I am successfully using Dataflash with a couple of different custom boards based on AT91RM9200 (DK like) Please post your u-boot configuration, your memory specification, and what you want to do.
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U-Boot 1.1.4 (May 20 2006 - 11:18:53)
U-Boot code: 21F00000 -> 21F165A4 BSS: -> 21F33404 RAM Configuration: Bank #0: 20000000 64 MB Atmel: AT49BV6416 (64Mbit) Flash: 8 MB DataFlash:AT45DB642 Nb pages: 8192 Page Size: 1056 Size= 8650752 bytes Logical address: 0xC0000000 Area 0: C0000000 to C0007FFF (RO) Area 1: C0008000 to C001FFFF (RO) Area 2: C0020000 to C0027FFF Area 3: C0028000 to C083FFFF In: serial Out: serial Err: serial
U-Boot> flinfo DataFlash:AT45DB642 Nb pages: 8192 Page Size: 1056 Size= 8650752 bytes Logical address: 0xC0000000 Area 0: C0000000 to C0007FFF (RO) Area 1: C0008000 to C001FFFF (RO) Area 2: C0020000 to C0027FFF Area 3: C0028000 to C083FFFF
Bank # 1: Atmel: AT49BV6416 (64Mbit) Size: 8 MB in 135 Sectors Sector Start Addresses: 10000000 (RO) 10002000 (RO) 10004000 (RO) 10006000 (RO) 10008000 (RO) 1000A000 (RO) 1000C000 (RO) 1000E000 (RO) 10010000 (RO) 10020000 (RO) 10030000 (RO) 10040000 (RO) 10050000 (RO) 10060000 (RO) 10070000 .snip.
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Ciao