Thanks zevia for this information and tests.
Regarding drives MediaTek chip, I think it’s sufficient to say it is a [B]MT1898E[/B].
Next part in your line is production time, year+week. (Don’t know about “AOBL” though, but it’s on all “Samsung SH-S182” chips I’ve seen around). “P2KN9” is most probably just a serial number.
Picture at right is drives SDRAM memory. (The more interesting part eeprom is on opposite side of pcb.)
Hope someone here is able to interpret and share more information about markings on MT1898E chip and what type of eeprom these drives use.