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Tube❄️Time

i've got another ST-225N to try and extract firmware from. the board was apparently dead, but eventually i might try it out with my other ST-225N logic board (i hope it still works)

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Tube❄️Time replied to Tube❄️Time

just have to move this hacked up ST-225 logic board over. it's cabled to an Arduino that runs the stepper motor so i can get to the hidden tracks.

Tube❄️Time replied to Tube❄️Time

it spins up and i've captured the negative tracks! (the Marker bit is a signal pulsed by the Arduino when it changes tracks or heads. it just cycles through all the heads in order, then goes to the next track)

Saleae Logic screenshot. channels are Hall, Marker, MFM Data.
Tube❄️Time replied to Tube❄️Time

looks like this came out of an Apple system. this is on track 0 which is user data.

Tube❄️Time replied to Tube❄️Time

track -1, head 0, sector 19 contains the drive serial number as ASCII text. interesting.

Tube❄️Time replied to Tube❄️Time

and we've got copyright text at track -1, head 0, sector 0.

Tube❄️Time replied to Tube❄️Time

track -2 contains the same 32 sectors on all heads. it seems to be 8051 code (02 is the LJMP instruction). i'm guessing this is the main drive operating code.

The Penguin of Evil replied to Tube❄️Time

@tubetime Lot of drives had the firmware on hidden tracks. I am entertained that it's an 8051 though. The newer drives got much better CPU

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