On 5/3/2012 4:25 PM, Harold Hallikainen wrote:
> y
> I suspect tokenized Basic is stored in RAM while the interpreter remains
> in flash. I think the original poster is looking at running the bootloade=
r
> in RAM so he can overwrite boot flash. This, to me, is dangerous, but I
> guess it could be done. You could end up with a dead box with nothing in
> flash.
>
>
> Harold
>

In quite a few of the Mips based processors in things like DVD players=20
they are set up with two different loaders. The first is installed in=20
non volatile ROM and loads the real boot loader. The first boot loader=20
application doesn't have very many functions , just tftp options, or=20
transferring the boot loader code from other sources.  This is a sample=20
from such a player showing how it first loads the permanent CFE=20
application that then loads BUPE the real bootloader application . Using=20
CFE you can replace BUPE but CFE remains intact.

''
BCM74430010
Setting NAND Params
CFE starting from ROM
Starting code in RAM
Booting Secured uCFE...
BCM97601 B0-BSEC  uCfe v2.1.22 (CFE core v2.1, BSP_REV 22), Endian Mode:=20
Little
Build Date: Mon Jan 25 15:37:45 EST 2010 (kdasu@stb-mhtb-04)
Copyright (C) Broadcom Corporation.
DDR                        : Bank0:128MB@400MHz | Bank1:256MB@400MHz
NAND Boot                  : FlashSize 512MB on CS0, BlkSize 128KB,=20
PgSize 2048B
NAND vendor timing         : addc1095 HYNIX HY27UF084G2B SLC =20
t1(33535238) t2(80000b78)
BUPE     bootline< boot -elf flash0.cfe.0: >Loader:elf Filesys:raw=20
Dev:flash0.cfe.0 File: Options:(null)
Loading: 0x87000000/22500 0x870057e4/127 0x87005880/2227=20
0x87007efc/596020 0x87099740/288 0x87099860/542800
Successfully loaded secure elf image....
Entry address is 0x87000000
Starting program at 0x87000000

""
It is very similar to what you suggest with the SPI flash.
Mark


--=20
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