[U-Boot-Users] u-boot on top of another bootloader

[Wolfgang Denk]

Dear François-Xavier,

in message <DA5CB450F843D611823E0002A5D4DB3C01FFD0B8 at renexch1.rennes.thmulti.com> you wrote:
>
> Then I decided where to flash u-boot. On a ppc cpu, the processor first
> jumps at address 0xfffffffc. At this very address there is a branch
> instruction to a bootloader. For example, with the original bootloader > this

Please don't make such statements. They may be correct on your system
(which obviously uses a IBM 4xx processor), but  they  are  wrong  on
most other systems. For example, no Motorola PowerPC processor that I
know  of  uses  0xFFFFFFFC  as reset entry point. Nor does any ARM or
MIPS based system.

Also, checking the register initialization may have  worked  in  your
case,  but  it  does  not  help in the general case like when unknown
board hardware (like a FPGA) needs to be  initialized  or  set  to  a
certain  state.  In  such  a  case  you  are  LOST  without  adequate
documentation from the manufacturer.

On the  other  hand,  there  are  usually  other,  better  documented
hardware solutions around :-)

Best regards,

Wolfgang Denk

-- 
Software Engineering:  Embedded and Realtime Systems,  Embedded Linux
Phone: (+49)-8142-4596-87  Fax: (+49)-8142-4596-88  Email: wd at denx.de
What is research but a blind date with knowledge?      -- Will Harvey