Q: How to implement persistent storage with overlayroot and UBIFS on NAND flash? Answer For NAND-based systems (IoT gateways industrial controllers): use UBIFS on top of UBI (Unsorted Block Images) for wear-leveling and bad block management. Create: ubiattach /dev/ubi_ctrl -m…
Q: How to use Device Tree (DTS) overlays for configuring hardware on embedded Linux? Answer Device Tree overlays (.dtbo) dynamically modify the base .dtb to enable/configure hardware without rebuilding the kernel. Create overlay: write a .dts with a fragment@0 {…
Q: How to boot embedded Linux over the network (NFS root) for development? Answer Network boot eliminates flash writes during development. Configure U-Boot: setenv ipaddr setenv serverip setenv bootargs root=/dev/nfs nfsroot=:/path/to/rootfs rw ip=dhcp. On the host: install nfs-kernel-server export the…
Q: How to implement real-time constraints on embedded Linux with PREEMPT_RT? Answer The PREEMPT_RT patch makes the Linux kernel fully preemptible reducing worst-case interrupt latency from >100 us to
Q: How to configure and use GPIO interrupts in embedded Linux userspace? Answer Userspace GPIO access via libgpiod (Linux 4.8+): use gpiochip device files in Command-line: gpioset gpiochip0 23=1 to set gpioget gpiochip0 23 to read. For interrupts use…
Q: How to reduce embedded Linux memory footprint from hundreds of MB to OpenRC or runit. (3) Strip binaries with strip –strip-unneeded. (4) Use static linking for simple utilities. (5) Disable glibc locales (locales-all is huge). (6) Compile with -Os…
Q: What is the best way to manage read-only root filesystems on embedded Linux? Answer Read-only rootfs is essential for embedded systems reliability and security. Implement overlayfs on top of a read-only squashfs root: mount overlayfs with upperdir on tmpfs/ramfs…
Q: How to implement secure OTA firmware updates on embedded Linux devices? Answer Secure OTA on embedded Linux: (1) Use A/B partition scheme – write to inactive partition verify then switch boot. (2) Authenticate with asymmetric signature: sign firmware with…
Q: How to configure and debug the Linux network stack for real-time Ethernet applications? Answer For real-time Ethernet (IEEE 1588 PTP TSN): configure the network stack with proper socket buffers (net.core.rmem_max) and interrupt coalescing (ethtool -C). Use XDP (eXpress Data…
Q: How to write a Linux kernel device driver for custom hardware (I2C/SPI/GPIO)? Answer For I2C/SPI kernel drivers: use the Linux kernel subsystem APIs. I2C: implement struct i2c_device_id table and probe()/remove() functions using i2c_master_send()/i2c_master_recv(). SPI: use struct spi_device with spi_write_then_read()…