From 4a32ffc6a5cd32c2ffa4caff90ba87c011968ee8 Mon Sep 17 00:00:00 2001 From: Michal Moskal Date: Fri, 30 Nov 2018 19:42:27 -0800 Subject: [PATCH] More info on familyID --- README.md | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/README.md b/README.md index ff4c2e4..78de586 100644 --- a/README.md +++ b/README.md @@ -84,12 +84,21 @@ If you're developing your own bootloader, and your board family isn't listed here, pick a new family ID at random. It's good to also send a PR here, so your family can be listed. +If the `familyID` doesn't match, the bootloader should disregard the +entire block, including `blockNo` and `numBlocks` fields. +In particular, writing a full UF2 file with non-matching `familyID` +should not reset the board. +This also allows for several files with different `familyID` to be +simply concatenated together, and the whole resulting file to be copied +to the device with only one actually being written to flash. + #### Picking numbers at random The reason to pick numbers at random is to minimize risk of collisions in the wild. Do not pick random numbers by banging on keyboard, or by using `0xdeadf00d`, `0x42424242` etc. A good way is to use the following shell command: `printf "0x%04x%04x\n" $RANDOM $RANDOM` +This procedure was unfortunately not used for the SAMD51 below. #### Family list