Hi @Martin_Kim
I also always boot from eMMC. The SDCard is just extra file space to store the source and the intermediate objects. the install step will move all of the OpenCV libraries to the eMMC. In order to complete the build you do need a swap space, the instructions above add a 1.5GB swap space on the eMMC.
I formatted the SDCard as a ext4 partition, then built a symbolic link to it from the home directory. After that I cd to the SDCard and do the OpenCV download and build on the SDCard. The SDCard is NOT the boot device, it is just extra file system space.
To convert a SDCard to ext4 file system, first run gdisk (the last sector numbers will be different depending on the size of your SDCard, just accept the defaults)
sudo gdisk /dev/mmcblk1
Command (? for help): o
This option deletes all partitions and creates a new protective MBR.
Proceed? (Y/N): y
Command (? for help): n
Partition number (1-128, default 1):
First sector (34-123764702, default = 2048) or {+-}size{KMGTP}:
Last sector (2048-123764702, default = 123764702) or {+-}size{KMGTP}:
Current type is 'Linux filesystem'
Hex code or GUID (L to show codes, Enter = 8300):
Command (? for help): w
Final checks complete. About to write GPT data. THIS WILL OVERWRITE EXISTING PARTITIONS!!
Do you want to proceed? (Y/N): y
You need to reboot the system after running gdisk.
Next build a file system on the SDCard, and link it to your home directory (you may need to reboot after the mkfs step):
sudo mkfs –t ext4 /dev/mmcblk1p1
cd /media/linaro/<long name>
sudo mkdir workspace
sudo chown linaro.linaro workspace
cd ~
ln –s /media/linaro/<long name>/workspace workspace
cd workspace
Full disclosure: I am an employee of Qualcomm Canada, any opinions I may have expressed in this or any other post may not reflect the opinions of my employer.
I’m also thinking of creating a ppa repo as it will make the life easier.