+---------------------------+-------------+-------------+
0x00 | codename ("g.soleil") | FF FF FF FF |Magic(txt)?->|
+---------------------------+-------------+-------------+
0x10 |--> Magic(Text)? |kernel crc32 |kernel length|
+-------------+-------------+-------------+-------------+
0x20 |rootfs crc32 |rootfs offset|rootfs length| 00 00 00 00 |
+-------------+-------------+-------------+-------------+
0x30 | Version (Text) |
+-------------------------------------------------------+
rootfs長はパディング無しの実サイズ
