FIRMWARE.md

Firmware notes

ASFileHeader

Field	Type	Size	Notes
Marker	[8]byte	8	Can be either Phyton\x00\x00 or AlmaCode.
Header Size	uint32	4	Size of whole Header struct. Fields may be omitted if they exceed the size.
Date Time	uint32	4	Release time in FirmwareDateTime encoding.
Buffer Size	uint32	4	TBD
Serial Number	[16]byte	16	Firmware coded for a specific device S/N. Usually all zeros.
Version Low	uint8	1
Version High	uint8	1
Version	-	-	Derived from Version Low and Version High. fmt.Sprintf("%d.%02d", VersionHigh, VersionLow)
File Count	uint32	4	TBD. Only used if Marker == AlmaCode
Firmware Header Size	uint32	4	TBD
Compressed	bool	1	Set to 1 on files with compressed FirmwareBlock.
Reserved	uint8	1	Set to 0.
CRC32	uint32	4	Contains the CRC of Data.
Data	[]byte	len(buf) - Buffer Size	In case of Marker == Phyton\x00\x00, []FirmwareBlock follows until EOF. Refer to source code to decode AlmaCode format.

DateTime

package radiacode

import "time"

func DateTimeToTime(dt uint32) time.Time {
	high := uint16(dt >> 16)
	low := uint16(dt)

	year := ((high >> 9) & 127) + 1980
	month := (high >> 5) & 15
	day := high & 31
	hours := (low >> 11) & 31
	minutes := (low >> 5) & 63
	seconds := (low & 31) * 2

	return time.Date(int(year), time.Month(month), int(day), int(hours), int(minutes), int(seconds), 0, time.UTC)
}

Block

Field	Type	XOR Key	Size	Notes
Header Size	uint32	-	4	Denotes the size of the header. Should be 12, but some weird cases exist in firmware to pad it, 0 value, or 0xFFFF?.
Size	uint32	0xCE27A932	4
Addr	uint32	0xB2D5A864	4	Denotes the location of Data in Flash.
Size Aligned	-	-	-	Derived from Size, 8 byte alignment. See Size Aligned derivation
Key Data	[512]byte	-	512	Encryption keys
Data	[]byte	-	Size Aligned

After each FirmwareBlock a new one follows, or EOF. So far each new one addresses the next memory block sequentially, without gaps.

Note that if ASFileHeader has Compressed field set, the Data will be smaller than the actual region.

Size Aligned derivation

package radiacode

func AlignSize(size uint32) uint32 {
	if (size % 8) != 0 {
		size = (size & uint32(0xFFFFFFF8)) + 8
	}
	return size
}

Encryption of Block Key + Data

See Encryption notes

Compression of FirmwareBlock Data

See Compression notes