Pi 5: Unable to Disable "lg" GPIO Driver via Overlay or Kernel Command Line (HATs Cannot Access GPIO)

Start by reproducing the reported state with gpioinfo after applying dtoverlay=gpio-no-lg in /boot/firmware/config.txt and gpiolib_lg=0 in /boot/firmware/cmdline.txt. Trace how the Raspberry Pi 5 "lg" GPIO driver handles those settings; done means GPIO17 and GPIO22 are no longer claimed and the HAT can access them.

Describe the bug

Summary:
On Raspberry Pi 5 running Raspberry Pi OS Bookworm (kernel 6.12.25, aarch64), the new "lg" GPIO driver claims GPIO pins (e.g., 17 and 22) by default. Attempts to disable the "lg" driver using dtoverlay=gpio-no-lg in /boot/firmware/config.txt or gpiolib_lg=0 in /boot/firmware/cmdline.txt have no effect. This prevents HATs like the Pimoroni Inky Impression from working, as they cannot access the required GPIO pins.

Steps to reproduce the behaviour

Steps to Reproduce:

1. Fresh install of Raspberry Pi OS Bookworm (64-bit) on Raspberry Pi 5.
2. Add dtoverlay=gpio-no-lg to /boot/firmware/config.txt and reboot.
3. Alternatively, add gpiolib_lg=0 to /boot/firmware/cmdline.txt and reboot.
4. Check pin status with gpioinfo | grep -E "17|22".

Device (s)

Raspberry Pi 5

Bootloader configuration.

Expected Result:
GPIO17 and GPIO22 should be unused and available for HATs after disabling the "lg" driver.

Actual Result:
GPIO17 and GPIO22 remain claimed by the "lg" driver, regardless of overlay or kernel command line settings.

Diagnostics:

• /boot/firmware/config.txt (last lines):

  dtoverlay=i2c1
  dtoverlay=i2c1-pi5
  dtoverlay=spi0-0cs
  dtoverlay=gpio-no-lg
  

• /boot/firmware/cmdline.txt (added at end of line):
  gpiolib_lg=0
• uname -a:

  Linux raspberrypi 6.12.25+rpt-rpi-v8 raspberrypi/rpi-eeprom#1 SMP PREEMPT Debian 1:6.12.25-1+rpt1 (2025-04-30) aarch64 GNU/Linux
  

• cat /etc/os-release:

  PRETTY_NAME="Raspbian GNU/Linux 12 (bookworm)"
  

• gpioinfo | grep -E "17|22" (after reboot):

  line  17:     "GPIO17"         "lg"  output  active-high [used]
  line  22:     "GPIO22"         "lg"   input  active-high [used pull-up]
  

What I've Tried:

• Verified correct config file (/boot/firmware/config.txt).
• Tried both overlay and kernel command line methods.
• Fully updated OS and firmware.
• Rebooted after each change.

Impact:
This prevents use of HATs and add-ons that require direct GPIO access on Pi 5 with Bookworm.

Request:
Please advise on a workaround or fix, or clarify if this is a known issue with the current Pi 5/Bookworm stack.

Thank you!

System

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Bootloader logs

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USB boot

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NVMe boot

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Network (TFTP boot)

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