[U-Boot-Users] [Fwd: Re: reducing size of u-boot binary]
Jerry Van Baren
gerald.vanbaren at ge.com
Mon Dec 17 14:38:44 CET 2007
> On Fri, 2007-12-14 at 07:20 -0500, Jerry Van Baren wrote:
>> vibi wrote:
>>> can any one please tell me how to reduce the size of u-boot.bin.
>>> i tried by disabling commands in the
>>> include/config/at91rm9200dk.h,as per the read me document
>>> even after this when i compile,i was unable to decrease the
>>> thanks in advance.
>>> vibi sreenivasan
>> How big is your binary, why do you need to reduce its size? I ask
>> because most of the time this question is the result of a link gone bad
>> where part of the linked binary lives in low memory space and part lives
>> in high memory space. As a result, the .bin has a huge amount of filled
>> (unused) data between the two.
>> Best regards,
> dear jerry,
> thanks for your reply.i am using u-boot 1.1.5 .my binary is only 90kb &
> i still wanted to reduce the size.i thought compiling u-boot is like
> compiling linux kernel,ie source file for the disabled commands wont get
> compiled,now i understood that i was wrong.
> i wanted to reduce size to less than 90kb because of constraints in
> available flash memory space.
> i have done it by disabling bootp & rarp by using #define macros
> i didnt find option for that in /include/cmd_confdefs.h .
> once again i thank you for your response
> thanks & regards
> vibi sreenivasan
90K is already pretty small for a u-boot image. I don't know how small
u-boot can get, but rule of thumb is 128K is a reasonable size for good
With respect to the commands, disabling commands should cut the actual
command code out via #ifdefs, so disabling commands should result in a
smaller image, even though all the files are still compiled.
a) There is a limit to how much can be cut out by removing commands.
There still is a lot of support code necessary.
b) It is possible that a command that is disabled needs a support
function, but the support function isn't disabled so not all the
potential savings are realized.
Note that u-boot is going to a better configuration and linking
methodology that doesn't compile unused pieces (as opposed to compiling
code that is #ifdefed out). I don't expect this to save any significant
amount of memory, but it is possible that it will turn up and fix errors
or inefficiencies with the current method.
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