Much thanks for that link. After looking at the proposed linux kernel patches, I was able to build a working ectool from DHowett’s repo, with just this tweak (I am a bit surprised this was sufficient):
--- a/include/ec_commands.h
+++ b/include/ec_commands.h
@@ -120,7 +120,7 @@ extern "C" {
#define EC_LPC_CMDR_SCI BIT(5) /* SCI event is pending */
#define EC_LPC_CMDR_SMI BIT(6) /* SMI event is pending */
-#define EC_LPC_ADDR_MEMMAP 0x900
+#define EC_LPC_ADDR_MEMMAP 0xE00
#define EC_MEMMAP_SIZE 255 /* ACPI IO buffer max is 255 bytes */
#define EC_MEMMAP_TEXT_MAX 8 /* Size of a string in the memory map */
$ make utils PREFIX=/usr
..
VERSION ec_version.h
HOSTCC util/ectool
$ sudo ./build/bds/util/ectool version
...
RO version: azalea_v3.4.113237-ec:66fc84,os
RW version: azalea_v3.4.113237-ec:66fc84,os
Firmware copy: RO
...
I’m, uh, not sure if there was a more obvious/intended way I should have known about, if this is old news or bad advice, my apologies 
(I first tried using the upstream framework repo branch “lotus-zephyr” which he mentioned is used for the AMD model, and I could not figure out how to just compile ectool, with appropriate board config includes …)