Returning a device to the Serial Loader

[michaelworster]

I have a device with a i.MX6 DualLite and eMMC for the primary storage device. When I initially booted the device it went into Serial Downloader mode and I used the MfgTool2.exe to flash in a valid image, once the tool completed I verified that I was able to successfully boot to the device.

Now I would like to return to Serial Downloader mode so that I could try out different images. How can I do that? When I boot now it no longer jumps to the Downloader because there is a valid image.

My first thought was to delete the Bootloader partition such that it would not find a valid image. I attempted this via:

=> mmc erase 2 8

MMC erase: dev # 0, block # 2, count 8 ...

Caution! Your devices Erase group is 0x400

The erase range would be change to 0x0~0x3ff

8 blocks erased: OK

However after rebooting I'm still seeing u-boot come up successfully, (however the kernel is now gone).

What way can I get my device back into Serial Downloader mode to reflash it?

[michaelworster · Accepted solution]

I resolved this issue by first marking the memory zone unsecured:

=> mmc partconf 0 1 1 1

Then erasing the flash and re-securing the part before rebooting:

=> mmc erase 0 4000

=> mmc partconf 0 1 1 0

[jimmychan]

is there any boot mode switch or jumper that you can change the boot mode?