JEEFS Header — Python Package

Pure Python library for the JEEFS EEPROM format used across JetHome devices. EEPROMHeaderV4 is the current board header and EEPROMHeaderV3 the fielded production one; constants and field offsets for every version (v1-v4) live in jeefs.constants. DeviceIdentityV1 handles the signed device.id record, and build_image / parse_image assemble and read a whole EEPROM image for provisioning tooling. No native dependencies.

Installation

pip install jeefs

Dependencies

• Python >= 3.10
• No external runtime dependencies (uses stdlib struct, binascii)

Building / Development

cd python
uv venv .venv && uv pip install -e ".[test]"
.venv/bin/python -m pytest tests/ -v

API

EEPROMHeaderV3 — main dataclass

from jeefs.header import EEPROMHeaderV3

Creating a header

header = EEPROMHeaderV3(
    boardname="JetHub-D1p",
    boardversion="2.0",
    serial="SN-2024-001",
    mac="F0:57:8D:01:02:03",
)
binary = header.to_bytes()  # 256-byte binary

Parsing from binary

header = EEPROMHeaderV3.from_bytes(raw_data)
print(header.boardname)   # "JetHub-D1p"
print(header.mac)         # "F0:57:8D:01:02:03"
print(header.serial)      # "SN-2024-001"

CRC verification

# Instance method
header = EEPROMHeaderV3.from_bytes(data)
is_valid = header.verify_crc(data)

# Static method (no instance needed)
is_valid = EEPROMHeaderV3.verify_crc_static(data)

Validation

errors = header.validate()
if errors:
    print("Invalid:", errors)

Partition image

image = header.to_partition_image()  # 4096-byte flash image

Fields

SignatureAlgorithm enum

from jeefs.constants import SignatureAlgorithm

SignatureAlgorithm.NONE       # 0
SignatureAlgorithm.SECP192R1  # 1 (48-byte signature)
SignatureAlgorithm.SECP256R1  # 2 (64-byte signature)

Constants

from jeefs.constants import (
    EEPROM_MAGIC,          # b"JETHOME\x00"
    EEPROM_HEADER_SIZE,    # 256
    EEPROM_FIELDS,         # dict of {field: (offset, size)}
    EEPROM_CRC_COVERAGE,   # 252
    EEPROM_PARTITION_SIZE,  # 4096
)

Usage example

See examples/python/read_header.py — reads an EEPROM binary, prints version, CRC status, board name, MAC address, and full v3 fields.

Testing

cd python
python -m pytest tests/ -v

Format specification

• Header common properties
• Header v3
• Full format spec