關於從NAND FLASH啟動

今天將NAND 全部FORMAT以後，重新用NOR中的UBOOT向NAND中燒寫UBOOT,按道理應該是和NOR 中的UBOOT介面一樣才對。燒寫進去以後發現根本不是，一直提示如下資訊：##### EmbedSky BIOS for SKY2440/TQ2440 #####
Press Space key to Download Mode !
Booting Linux ...
Copy linux kernel from 0x00200000 to 0x30008000, size = 0x00200000 ... Copy Kern
el to SDRAM done,Warning: this binary is not compressed linux kernel image
zImage magic = 0xffffffff
NOW, Booting Linux......
undefined instruction
pc : [<30f0c550>]    lr : [<33d81760>]
sp : 33d3ded4  ip : c000107e  fp : bfefdfdd
r10: ffffffff  r9 : fbfcb3dc  r8 : 33d3ffdc
r7 : fbfbf725  r6 : 00000000  r5 : 000000a8  r4 : 30008000
r3 : c000107c  r2 : 30008000  r1 : 000000a8  r0 : 00000000
Flags: Nzcv  IRQs off  FIQs off  Mode SVC_32
Resetting CPU ...*** Warning - bad CRC or NAND, using default environment ##### EmbedSky BIOS for SKY2440/TQ2440 #####
Press Space key to Download Mode !
Booting Linux ...
Copy linux kernel from 0x00200000 to 0x30008000, size = 0x00200000 ... Copy Kern
el to SDRAM done,Warning: this binary is not compressed linux kernel image
zImage magic = 0xffffffff
NOW, Booting Linux......
undefined instruction
pc : [<30f0c550>]    lr : [<33d81760>]
sp : 33d3ded4  ip : c000107e  fp : bfefdfdd
r10: ffffffff  r9 : fbfcb3dc  r8 : 33d3ffdc
r7 : fbfbf725  r6 : 00000000  r5 : 000000a8  r4 : 30008000
r3 : c000107c  r2 : 30008000  r1 : 000000a8  r0 : 00000000
Flags: Nzcv  IRQs off  FIQs off  Mode SVC_32
Resetting CPU ...*** Warning - bad CRC or NAND, using default environment怎麼會這樣呢，同樣燒寫的是UBOOT，為什麼會不不同呢，後來一問群主，他說是因為沒有燒寫核心。我說我是沒有燒寫核心啊，我剛才把NAND全格了，然後燒寫了UBOOT，為什麼不一樣。樓主說開機按SPACE鍵，就一樣了，因為NAND FLASH開機預設的是8：boot system，提示的資訊就說找不到核心。這下我明白了。我又做了一個實驗，從NOR啟動，按後選8：boots system 結果個剛才的現象一樣。再看看啟動時的提示資訊：Enter your selection: 8
Start Linux ...
Copy linux kernel from 0x00200000 to 0x30008000, size = 0x00200000 ... Copy Kern
el to SDRAM done,NOW, Booting Linux......
Uncompressing Linux.............................................................
............................................................. done, booting the
kernel.無論從哪種方式啟動，都是從ox00200000這個地方把kernel（核心）複製到SDRAM的0x30008000中去，（SDRAM的其真實位址是0x30000000）然後開始啟動核心。