Copying the relevant info to the bug:

In terms of backporting the current trunks_send, yes, should be (almost) as easy as taking the latest code for it. It's meant to be a relatively simple tool using just the raw SendMessage feature of trunks, so it's almost independent from the rest of the trunks code.

To backport you need to pick all missing commits for trunks_send.cc (which is all 7 for factory-reef-8811.B; and the last 4 for factory-gru-9017). Since factory-reef doesn't have trunks_send at all yet, there, besides all trunks_send.cc commits, you also need CL:405728 to make some constants available to trunks_send and CL:402069 to add the tool to the image in ebuild. After that, it should build and work (didn't test).

BTW, this is NOT a hard requirement.

Gru & Reef factory branches already support updating via usb_updater (as upstart). However, using that implies whenever ANY projects are going to change FSI, they have to push new Cr50 binary to factory branches, get a new build of test image and push to factory. This is how we update Cr50 today for Gru&Reef.

Starting from Poppy, they'll update with trunks_send, which is more convenient since it always grabs FSI, no need to change test images.

So, I'll leave the decision to SIE. If you're ok with pushing Cr50 binaries to factory branches periodically then we don't need trunksd_send.

also, trunks_send works just fine with 0.0.13

Will find time slot to investigate it.

CLs for back porting to Gru is submitted - https://chromium-review.googlesource.com/#/c/564918/

Back porting to Gru is done with a issue fix.

Back port to Reef is done as well.