Err, #4 will work, just not very convenient. the netbsd will have a uboot in the 1st 16M
(to disable you have to unnecessisarily remove and then re-install back cover, why is there not a hole?))
#5 save emmc mbr, save emmc 1st 16M, blank 1st 16M. restore mbr
Then only the uboot on SD is available, and then you can actually evaluate a SD uboot
How to boot from emmc then? either tow-boot on SD (+ whatever distro) OR
Just a uboot on a preferably small SD, the rest can be a data drive
Do put a file system on the rest, or uboot will freak out, lock up
A good way to test uboots
And, BTW, if you have a working uboot, DON'T be in a hurry to update it,
ask yourself ,,,,WHY (and make a backup, so you can change your mind)
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BTW, be aware that, for rk3399, uboot on SPI is DIFFERENT than uboot on SD/emmc,m,,,, use right one
(to disable you have to unnecessisarily remove and then re-install back cover, why is there not a hole?))
#5 save emmc mbr, save emmc 1st 16M, blank 1st 16M. restore mbr
Then only the uboot on SD is available, and then you can actually evaluate a SD uboot
How to boot from emmc then? either tow-boot on SD (+ whatever distro) OR
Just a uboot on a preferably small SD, the rest can be a data drive
Do put a file system on the rest, or uboot will freak out, lock up
A good way to test uboots
And, BTW, if you have a working uboot, DON'T be in a hurry to update it,
ask yourself ,,,,WHY (and make a backup, so you can change your mind)
-----
BTW, be aware that, for rk3399, uboot on SPI is DIFFERENT than uboot on SD/emmc,m,,,, use right one