[U-Boot-Users] 2-step U-boot(?)
Hello,
I'm new to u-boot. Has anybody tried to make 2-step u-boot? I mean a really small u-boot (the first u-boot) possible only needs to initialize the CPU, memory... and load the full featured (the second u-boot) u-boot and the Linux to the RAM. In this way the second u-boot as an application can be updated on the fly.
Could you please share your knowledge here If you have done the job or the similar?
Regards,
On Monday 09 June 2008, Frank Wei wrote:
I'm new to u-boot. Has anybody tried to make 2-step u-boot? I mean a really small u-boot (the first u-boot) possible only needs to initialize the CPU, memory... and load the full featured (the second u-boot) u-boot and the Linux to the RAM. In this way the second u-boot as an application can be updated on the fly.
Could you please share your knowledge here If you have done the job or the similar?
Yes, there already is a framework for a 2-stage U-Boot booting in place. Take a look at the nand_spl (NAND Secondary Program Loader) infrastructure:
nand_spl/* doc/README.nand-boot-ppc440
Here a small (4k) image is build which only inits the basic CPU stuff, RAM and NAND controller. Then a full-blown U-Boot image is loaded from NAND.
Best regards, Stefan
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In message 52CF207E00A9394C8CD1423668654840A8B3DB1E@4rf-nz-exch02.local.4rf.com you wrote:
I'm new to u-boot. Has anybody tried to make 2-step u-boot? I mean a really small u-boot (the first u-boot) possible only needs to initialize the CPU, memory... and load the full featured (the second u-boot) u-boot and the Li
As Stefan already pointed out, booting from NAND involves exactly such a scenario.
nux to the RAM. In this way the second u-boot as an application can be upda ted on the fly.
However I don;t really understand what this has to do with the capability to update U-Boot? You can update U-Boot as is just fine.
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Best regards,
Wolfgang Denk
participants (3)
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Frank Wei -
Stefan Roese -
Wolfgang Denk