[U-Boot] Switch from mmcboot to ramboot?

How can I tell u-boot to boot with the ramboot= definition instead of mmcboot= ?
- Grant

Hi Grant,
How can I tell u-boot to boot with the ramboot= definition instead of mmcboot= ?
- Grant
You need to change environmental variable bootcmd
setenv bootcmd ramboot saveenv run bootcmd
or simpler:
Stop u-boot -> and access prompt
then,
run ramboot

How can I tell u-boot to boot with the ramboot= definition instead of mmcboot= ?
- Grant
You need to change environmental variable bootcmd
setenv bootcmd ramboot saveenv run bootcmd
or simpler:
Stop u-boot -> and access prompt
then,
run ramboot
Hi Lucasz, that didn't work for me and I think it's because of the variables set by 'make am335x_evm_defconfig'. It seems like there are a set of standard u-boot commands and a higher level of variables set by 'make am335x_evm_defconfig' which appear in include/configs/am335x_evm.h and prevent you from using the standard u-boot commands in uEnv.txt.
For example, even after adding the following to the top of my uEnv.txt:
setenv bootcmd ramboot saveenv
I still get:
"Booting from mmc ..."
I'm struggling to figure out how to use the framework provided by 'make am335x_evm_defconfig' in uEnv.txt. Can you point me to info on how to do that?
- Grant

Hi Grant,
How can I tell u-boot to boot with the ramboot= definition instead of mmcboot= ?
- Grant
You need to change environmental variable bootcmd
setenv bootcmd ramboot saveenv run bootcmd
or simpler:
Stop u-boot -> and access prompt
then,
run ramboot
Hi Lucasz, that didn't work for me and I think it's because of the variables set by 'make am335x_evm_defconfig'. It seems like there are a set of standard u-boot commands and a higher level of variables set by 'make am335x_evm_defconfig' which appear in include/configs/am335x_evm.h and prevent you from using the standard u-boot commands in uEnv.txt.
I can give you an example with Samsung's soc.
When you execute 'make trats_defconfig' then default envs defined at include/trats.h are compiled in.
Then if envs are broken (or not available), then those values are default.
Please type ? at u-boot prompt and look for env commands. When you type the command, then context help appears.
On Samsung's SoCs you can easily write those default envs to memory (oneNAND or eMMC) with 'envs default'. And then edit those stored values (as I've written previously).
For example, even after adding the following to the top of my uEnv.txt:
I'm not familiar with am335x_evm board and I don't know what is the purpose of uEnv.txt.
I may just guess, that this is a default command list to execute.
Please investigate the "env" command if it can work for you.
setenv bootcmd ramboot saveenv
I still get:
"Booting from mmc ..."
I'm struggling to figure out how to use the framework provided by 'make am335x_evm_defconfig' in uEnv.txt. Can you point me to info on how to do that?
- Grant
Regards, Lukasz
participants (3)
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Grant
-
Lukasz Majewski
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Lukasz Majewski