OS upgrade causes "Inappropriate ioctl for device" (Error 25)

[plsherman]

I'm building a new Pi3 that uses all of the IO pins to control relays or monitor switches/sensors. The software I wrote was working perfectly until I did an OS upgrade. After the upgrade, the application failed when it attempted to define an IO pin as an output. The OS upgrade apparently activated both SPI and I2C functions which caused this failure. The application worked without issues after applying the fix below.

Fix:
Use raspi-config to disable SPI and I2C.

[taartspi]

Were you using GPIO2 or GPIO3 as an output ? Likely yes, so the I2C being enabled created the error. Thanks for the debug detail/fix. The upgrade should not be changing your HW configuration. Same question for SPI as default the overlay looks to use 5 GPIOs

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On Sun, Jun 28, 2026 at 10:57 AM plsherman ***@***.***> wrote: I'm building a new Pi3 that uses all of the IO pins to control relays or monitor switches/sensors. The software I wrote was working perfectly until I did an OS upgrade. After the upgrade, the application failed when it attempted to define an IO pin as an output. The OS upgrade apparently activated both SPI and I2C functions which caused this failure. The application worked without issues after applying the fix below. Fix: Use raspi-config to disable SPI and I2C. — Reply to this email directly, view it on GitHub <#680?email_source=notifications&email_token=AK5A325AV3GQCNJT7C43MM35CE57ZA5CNFSNUABBM5UWIORPF5TWS5BNNB2WEL2ENFZWG5LTONUW63RPGEYDGMZUGE3TRJTSMVQXG33OVJZXKYTTMNZGSYTFMSSWK5TFNZ2KYZTPN52GK4S7MNWGSY3L>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AK5A32YCOK5R5N44X7WULH35CE57ZAVCNFSNUABIKJSXA33TNF2G64TZHMYTSMRVHEYTMMZRHNCGS43DOVZXG2LPNY5TCMBTGM2DCNZYUF3AE> . You are receiving this because you are subscribed to this thread.Message ID: ***@***.***>