The main things to #ifdef out are: - The ram init code. - The serial init code - the bat init code - the cache in ram trick and point the stack to an unused area of memory. - The relocate_code function since you are already in ram. - make sure you change the TEXT_BASE variable to point to the area in ram you want to run.
I've done this (ran u-boot from ram) on many different boards and it's not that diifcult if you know what you're doing.:-) BTW, bedbug comes in handy since the symbol addresses map directly to the link addresses...
--- "Robert P. J. Day" rpjday@mindspring.com wrote:
(i posted something similar to this on the SF forum before i realized there was a real mailing list. oops.)
before i commit myself to reflashing with u-boot, i'd like to know if it's possible to just load it into RAM and use the current bootloader to jump to it, just to see the menu come up, nothing more.
working with an 8xx board, 850DE-based, and as a test, i did a configure with RPXlite_config (even though, technically, it's not exactly an RPXlite but close). generated u-boot.bin and used embedded planet's planet core (PC) bootloader to download it into RAM. at this point, am i allowed to just use PC to
g <download address> ??
we could do that with PC -- compile a new version, download it to RAM and jump to it, just to see that it seemed to function at the basic level.
thoughts? i've tried it, and every time i use PC to transfer control, i get nothing -- immediate hang. maybe a serial comms problem? who knows?
rday
SF.Net email is sponsored by Shop4tech.com-Lowest price on Blank Media 100pk Sonic DVD-R 4x for only $29 -100pk Sonic DVD+R for only $33 Save 50% off Retail on Ink & Toner - Free Shipping and Free Gift. http://www.shop4tech.com/z/Inkjet_Cartridges/9_108_r285 _______________________________________________ U-Boot-Users mailing list U-Boot-Users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/u-boot-users
__________________________________ Do you Yahoo!? New and Improved Yahoo! Mail - 100MB free storage! http://promotions.yahoo.com/new_mail