JMS576/7/8/9 EEPROM offsets:

0x00 - 0x01: USB VID (little endian)
0x02 - 0x03: USB PID (little endian)
0x08 - 0x09: USB BCD?
0x0A: 0x0A = use SCSI strings on 0xC8-0xDF, anything else = use ATA drive ID for SCSI vendor/product
0x0C - 0x2F: String Descriptor 1 - Manufacturer
(some firmware dumps may feature a bogus/empty string descriptor at 0x1B)
0x30 - 0x53: String Descriptor 2 - Product
0x54 - 0x77: String Descriptor 3 - Serial Number (descriptor size)
(0x54 set to 0 = use serial number from attached drive)

0x78 - 0xC7: 0

0xC8 - 0xCF: SCSI vendor
0xD0 - 0xDF: SCSI product name

0xE0 - 0xE1: "HD"
0xE2: 0
0xE3: generally 0 (0x14 on 01.02.01.04 Orico)
0xE4 - 0xE6: 0

0xE7: Features bitmap 1
bit 7: enable USB Mass Storage / BOT
bit 6: enable UASP
bit 5: enable 4Kn sector emulation ("Multisec")
bit 4: always unset
bit 3: always unset
bit 2: ???
bit 1: always set
bit 0: ???

0xE8 - 0xEF: 0
OxF0 - 0xF1: "BC"

0xF2: Features bitmap 2
bit 7: always unset
bit 6: ???
bit 5: always set
bit 4: ???
bit 3: enable powersave mode
bit 2: always unset
bit 1: always unset
bit 0: always unset

0xF3: Features bitmap 3???
bit 7: always set
bit 6: always set
bit 5: always unset
bit 4: always unset 
bit 3: generally unset (00.04.01.04 Self-Power+ODD has this set)
bit 2: always unset
bit 1: always unset
bit 0: ???

0xF4 - 0x05: 0

0xF6 - 0xF7: Powersave timeout in seconds (big endian!)

0xF8 - 0xFD: 40 0F 32 05 00 00

0xFE - 0XFF: EEPROM Identifier ("JM")

0x100 - 0x1FF: Junk data? (same on ALL EEPROM dumps)
MD5:   34a237c125b376b075debfaa6fbff386
SHA1:  137b6a3313f6fdf8e3a179eadb86e17b5aaedc7d
CRC32: 095ca824


USB String Descriptor format:
+0: UNICODE String length ((ANSI length + 1) * 2)
+1: Descriptor type (0x03)
+2...+n: ANSI string