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ARM ROM Boot Modes
The NAND User boot loader UBL descriptor format is described in
.
Table 11-1. NAND UBL Descriptor
Page 0 Address
32-Bits
Description
0
0xA1AC EDxx
Magic number (0xA1ACEDxx)
4
Entry Point Address of UBL
Entry point address for the user boot-loader (absolute address)
8
Number of pages in UBL
Number of pages (size of user boot-loader in number of pages)
12
Starting Block # of UBL
Block number where user boot-loader is present
16
Starting Page # of UBL
Page number where user boot-loader is present
Note:
The first 32-bytes of AIM are the ARM’s system interrupt vector table (IVT) (8 vectors,
4-bytes each). The UBL copy starts after the 32-byte IVT.
Different NAND boot mode options can be setting different MAGIC IDs in the UBL descriptor.
lists the UBL signatures.
Table 11-2. UBL Signatures and Special Modes
Mode
Value
Description
UBL_MAGIC_SAFE
0x A1AC ED00
Safe boot mode
UBL_MAGIC_DMA
0x A1AC ED11
DMA boot mode
UBL_MAGIC_IC
0x A1AC ED22
I Cache boot mode
UBL_MAGIC_FAST
0x A1AC ED33
Fast EMIF boot mode
UBL_MAGIC_DMA_IC
0x A1AC ED44
DMA + I Cache boot mode
UBL_MAGIC_DMA_IC_FAST
0x A1AC ED55
DMA + I Cache + Fast EMIF boot mode
Boot Modes
154
SPRUFB3 – September 2007