[U-Boot] Atmel AT91RM9200: U-Boot refuses to copy to a particular sector of flash memory

[Ki Chi Leung]

Hello list,

I am trying to load a Linux 2.6.22 kernel uimage on the flash memory
of a custom Atmel AT91RM9200 board. From U-Boot the flash memory map
is as follows:

U-Boot> flinfo
DataFlash:AT45DB161
Nb pages:   4096
Page Size:    528
Size= 2162688 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 C020FFFF

Bank # 1: Atmel: AT49BV163D (16Mbit)
  Size: 2 MB in 39 Sectors
  Sector Start Addresses:
    10000000 (RO) 10002000 (RO) 10004000 (RO) 10006000      10008000
    1000A000      1000C000      1000E000 (RO) 10010000 (RO) 10020000
    10030000      10040000      10050000      10060000      10070000
    10080000      10090000      100A0000      100B0000      100C0000
    100D0000      100E0000      100F0000      10100000      10110000
    10120000      10130000      10140000      10150000      10160000
    10170000      10180000      10190000      101A0000      101B0000
    101C0000      101D0000      101E0000      101F0000

I also have 2x 48LC8M16A2 modules (32MB, SDRAM, address 0x20000000 -
0x21ffffff) which I download the kernel to before copying to flash.

I have to copy the kernel into the flash starting at address
0x10020000 (lower addresses reserved by U-Boot apparently). However,
when I try to copy the 1018KB uimage, the copy always fails with
"flash not erased", even after the sectors have been unprotected and
erased. I found that if I copy anything into the sector starting at
0x10100000, U-Boot will fail to start from the flash. The sector in
question can be unprotected and erased without problems.

Is there any way to find out why U-Boot will not let me copy to this
sector, and why erasing and/or trying to copying to it would cause
U-Boot not to start anymore? Thanks in advance.

P.S. This is my first post here, apologies if I missed out any important info.