The system is based on OXE800SE(MBWEI) or OXE800DSE(MBWEII)
OXE800SE Datasheet
OXE800DSE Datasheet

Which includes ARM926EJ-S processor

Processor       : ARM926EJ-Sid(wb) rev 5 (v5l)
BogoMIPS        : 99.73
Features        : swp half thumb fastmult edsp java 
CPU implementer : 0x41
CPU architecture: 5TEJ
CPU variant     : 0x0
CPU part        : 0x926
CPU revision    : 5
Cache type      : write-back
Cache clean     : cp15 c7 ops
Cache lockdown  : format C
Cache format    : Harvard
I size          : 32768
I assoc         : 4
I line length   : 32
I sets          : 256
D size          : 32768
D assoc         : 4
D line length   : 32
D sets          : 256

Hardware        : Oxsemi NAS
Revision        : 0000
Serial          : 0000000000000000
Ethernet controller is AST Research (by VIA Technologies) VT6122 Gigabit Ethernet Adapter



Ram chips:
Hynix HY5DU561622E FP-J (TP-J) 256Mb (32MB) 1-disk models, older 2 disk models
Hynix HY5DU121622D TP-D43 512Mb (64MB) some newer 2 disk models
both are 166MHz 16Mx16 FBGA (60ball) 4bank, 2.5V, CL2.5

The disks are different in different versions

About U9 at the back of the board


This is an i2c-style bus, (or at least, the subset called "smbus") that apparently only was used for a non-existent Real-Time-Clock chip. Maybe some early version of these units had an on-board clock that would run when not powered on, and be used for setting date and time on start-up. Otherwise, the system would start at January 1 1970 … There are loaded modules and operating system support for this, but one of the mesages coming on the serial port on startup indicates that the clock chip is missing. Instead, the units use ntp (network time protocol) to get the date and time correct from the Internet.

Thus, it is possible to connect I2C peripherals, such as the PCF8574 digital IO circuit, DS1621 temperature sensor, or any of a large set of others to the MyBookWorld, and run programs there that access the hardware. The position on the circuit board, marked as U9, should have been this clock chip of the type M41T00, but it, and its supporting components are omitted in all the eight units that I have access to here. The two signal lines making up the I2C bus are SCL on pin 6 of U9, and SDA on pin 5 of U9. I also connected to ground, common, to pin 4 of U9. In addition, I used the 3.3V supply available from the serial port connection. This I2C bus runs on 3.3V, it is possible to make a voltage level translator with two NMOS transistors and some resistors, to run this at 5 V.

And even if this chip should be present, the I2C-bus is still available as long as we have devices with other slave addresses than the 0x68 that the clock chip uses. I have tested connecting a DS1621 and a PCF8574 to this I2C bus, and everything works as expected. You will have to do some careful "surgery" on the device to make these connections, and observe static discharge protection guidelines, so as not to kill the electronics, and of course, this will void any remaining warranty that might have survived the initial ssh-access hack.

From Elghund in this thread.

PCB Images:

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