06 - atomic update

diagrams/plantuml/ab-installation-sequence.puml

@@ -0,0 +1,48 @@
+@startuml
+title A/B preparation and activation
+skinparam shadowing false
+skinparam monochrome true
+participant "OTA manager" as Manager
+participant Installer
+database "Slot B" as B
+database "OTA progress" as Progress
+participant "Boot control" as Boot
+
+note over Manager, Boot
+  A is confirmed. B is inactive. No earlier trial is pending.
+  One installer owns B. A and shared data are preserved.
+end note
+Manager -> Progress : Save intent: release and target B
+Manager -> Installer : Prepare B
+Installer -> B : Write release
+Installer -> B : Complete required storage operations
+Installer -> B : Read and verify installed contents
+Installer --> Manager : Verified expected release
+note over Manager, Boot
+  Reset before activation: boot A.
+  Inspect B and verify again before a new activation request.
+end note
+Manager -> Progress : Save prepared release B
+Manager -> Boot : Save trial request for B
+Boot -> Boot : Persist target and attempt limit
+note right of Boot
+  Interrupted state write:
+  read valid old or new state,
+  or enter defined recovery.
+end note
+Boot --> Manager : Trial request saved
+note over Manager, Boot
+  Reset here: boot control may start B.
+  Old OTA progress must not cause a rewrite or fresh attempts.
+end note
+Manager -> Progress : Save trial-requested result
+Manager -> Boot : Restart into trial
+ref over Manager, Boot
+  Existing A/B trial boot, checks, and confirmation diagram
+end ref
+legend bottom
+  Success path only. Any error stops forward progress and requires state inspection.
+  Arrows assume completed durable operations under the platform storage contract.
+  A saved trial request is not confirmation.
+endlegend
+@enduml