PASS
AUTHENTIC IMAGE ONLY
Payload digest and Ed25519 signature are checked before flash mutation.
CORERUST / no_std
Verification evidence ↓Embedded security / fault injection / 01
Pull the plug.
Keep the trust.
A secure firmware update is not finished when a signature passes. It is finished when every interrupted write still leaves a device that can boot a trusted image.
HOST-SIDE MODEL · NOT PRODUCTION FIRMWARE · QEMU NOT YET VALIDATEDVIRTUAL TARGETFG-MPS2 / HOST MIRROR
INFO
FG-DEVBOARD / REV 1.0
UPDATE INFGU1
MASK ROMVERIFYEd25519 / SHA-256 / POLICY
MCUBOOT AWATCHDOG ARMED
QSPI FLASHSLOT A
IMAGEv1.0
SEQ0001
CONFIRMEDQSPI FLASHSLOT B
IMAGEEMPTY
SEQ0000
EMPTY verified / confirmed trial / write blocked / corrupt
01 / 08
receive
Package received
Manifest v1 · sequence 2 · Ed25519 signature · SHA-256 digest
UPDATE PATH OPEN
Security properties / 02
Trust is a state machine, not a green checkmark.
The Rust core verifies a signed manifest, writes only the inactive slot, commits redundant CRC-protected metadata, limits trial boots, and preserves a monotonic rollback floor.
PASS
ROLLBACK FLOOR
The signed sequence must increase and is never lowered during fallback.
PASS
BOOTABLE SLOT
An interrupted write never becomes the only boot candidate.
PASS
METADATA RECOVERY
The newest valid CRC-protected copy wins after reset.
03
Two implementations, clearly separated
Rust library
The real Ed25519, SHA-256, package parser, A/B state machine, CRC metadata, and exhaustive cut-point tests live infirmware/src. It compiles without unsafe code and has a no_std mode.
Browser mirror
This interface mirrors the policy transitions in TypeScript so every scenario stays interactive. It does not pretend the browser is running the Rust binary or an emulated microcontroller.
Host tested today
Hardware timing, flash drivers, ROM integration, and QEMU boot are outside version 1.0. The repository labels those as future work instead of treating a simulator as production evidence.