Using eMMC can kill the device

[Dysmas]

Developers should be aware that if they develop a system which does not have the FriendlyElec boot loader, but use the Mainline U-Boot, it they load this system in eMMC and anything happens which prevents the system to boot, there is NO WAY AT ALL to overcome the problem. Due to its design, the R5S (or R5C) will continue to boot on eMMC and will not boot on a SD Card. The only way to boot on SDCard is to mask the eMMC, and since it is masked, it is impossible to erase it or correct the problem. Since it is not always possible to be present at boot to mask the eMMC (this is manual), the device can become really unusable.
The RKDevTool provided does not work on these NanoPI. I tried with R5S and R5C, with 2.84 and 2.58 versions.

For Nanopi R5S boot order, see :
https://wiki.friendlyelec.com/wiki/inde ... nd_SD_card

If anyone founds a way to solve this problem, I would appreciate.

[electrified]

I had success with holding down the mask button for a shorter period of time.

Watch the output from the serial uart and release the mask button as soon as the booting from SD card starts. The eMMC will then be available and can be wiped/overwritten.

Also this video shows RKDevtool working on the R5S, so I believe it is working: https://www.youtube.com/watch?v=hlBwxLRXpGY