The log shows us that in mirror_mok_db() the call to get_max_var_sz() in mok.c:366 was successful, so it must hang before line 424 where dprint() is called. Given 19304 < 0x4FDC, I assume the path in 373 is being taken, and the call to SetVariable() inside there is hanging in the firmware (despite the variable being 1140 bytes shorter than the maximum allowed).
The log shows us that in mirror_mok_db() the call to get_max_var_sz() in mok.c:366 was successful, so it must hang before line 424 where dprint() is called. Given 19304 < 0x4FDC, I assume the path in 373 is being taken, and the call to SetVariable() inside there is hanging in the firmware (despite the variable being 1140 bytes shorter than the maximum allowed).