AM3352烧写程序后启动时找不到内核的情况？

最近在小批量，焊了30块，有5块板启动时找不到内核，提示如下：启动方式10011  从MMC烧写到NAND  然后从nand启动的
NAND read: device 0 offset 0x700000, size 0x80000
524288 bytes read: OK
## Booting kernel from Legacy Image at 80007fc0 ...
Image Name: Linux-3.2.0-ga894bde-dirty
Image Type: ARM Linux Kernel Image (uncompressed)
Data Size: 3089472 Bytes = 2.9 MiB
Load Address: 80008000
Entry Point: 80008000
Verifying Checksum ... Bad Data CRC
ERROR: can't get kernel image!
U-Boot#
使用mtest命令是这种：
U-Boot# mtest
Pattern 00000000 Writing... Reading...
Mem error @ 0x8434196C: found 000F065B, expected 000D065B
Mem error @ 0x846A0430: found 0018810C, expected 001A810C
Pattern FFFFFFFF Writing... Reading...
Mem error @ 0x8434196C: found FFF6F9A4, expected FFF2F9A4
Mem error @ 0x846A0430: found FFE77EF3, expected FFE57EF3
Pattern 00000001 Writing... Reading...
Mem error @ 0x8434196C: found 000F065C, expected 000D065C
Mem error @ 0x846A0430: found 0018810D, expected 001A810D
Mem error @ 0x846A0434: found 001A810C, expected 001A810E
Pattern FFFFFFFE Writing... Reading...
Mem error @ 0x8434196C: found FFF6F9A3, expected FFF2F9A3

怀疑是焊接或DDR质量问题，但是都重新焊接或者换了新的芯片，仍然是找不到内核！
请问各位有没有碰到过这种情况？？