Hi @tik
I fixed an issue that has to do with that not long ago. See this link:
Could you please try first of all if disabling CONFIG_MXC_PXP_V3 already solves your issue?
Some thoughts of my side on your questions:
I used the content of /proc/cmdline for --append. So Kernel command line will be no different to normal boot.
You have an eMMC module, no worries that will work. But be aware that with a NAND module U-Boot passes the NAND-Structure to the kernel on booting. If using kexec with a nand you have to add the NAND structure by yourself with the kernel parametermtdparts.
with M4 running: freeze after successful shutdown
U-Boot carves out some memory for RPMSG to work. I guess that could be the reason as on a boot with kexec the kernel is not aware that there is another guy writing in a certain memory region. See this commit
without M4 running: freeze immediately at different outputs at around 1.9 seconds
That looks familiar to me. I guess that could be a hint that it’s the CONFIG_MXC_PXP_V3 bug.
Best regards,
Philippe