Slim i586 live CD: root on CD, no initrd, lean kernel

.config

@@ -1,6 +1,6 @@
 #
 # Automatically generated file; DO NOT EDIT.
-# Buildroot 2025.02.17 Configuration
+# Buildroot -g430ecb4-dirty Configuration
 #
 BR2_HAVE_DOT_CONFIG=y
 BR2_HOST_GCC_AT_LEAST_4_9=y
@@ -472,7 +472,7 @@ BR2_GENERATE_LOCALE=""
 # BR2_SYSTEM_ENABLE_NLS is not set
 # BR2_TARGET_TZ_INFO is not set
 BR2_ROOTFS_USERS_TABLES=""
-BR2_ROOTFS_OVERLAY=""
+BR2_ROOTFS_OVERLAY="board/mentalnet/overlay"
 BR2_ROOTFS_PRE_BUILD_SCRIPT=""
 BR2_ROOTFS_POST_BUILD_SCRIPT=""
 BR2_ROOTFS_POST_FAKEROOT_SCRIPT=""
@@ -497,7 +497,7 @@ BR2_LINUX_KERNEL_USE_DEFCONFIG=y
 # BR2_LINUX_KERNEL_USE_ARCH_DEFAULT_CONFIG is not set
 # BR2_LINUX_KERNEL_USE_CUSTOM_CONFIG is not set
 BR2_LINUX_KERNEL_DEFCONFIG="i386"
-BR2_LINUX_KERNEL_CONFIG_FRAGMENT_FILES="localversion.config"
+BR2_LINUX_KERNEL_CONFIG_FRAGMENT_FILES="localversion.config board/mentalnet/linux-slim.config"
 BR2_LINUX_KERNEL_CUSTOM_LOGO_PATH=""
 BR2_LINUX_KERNEL_BZIMAGE=y
 # BR2_LINUX_KERNEL_VMLINUX is not set
@@ -509,7 +509,7 @@ BR2_LINUX_KERNEL_GZIP=y
 # BR2_LINUX_KERNEL_XZ is not set
 # BR2_LINUX_KERNEL_ZSTD is not set
 # BR2_LINUX_KERNEL_DTS_SUPPORT is not set
-# BR2_LINUX_KERNEL_INSTALL_TARGET is not set
+BR2_LINUX_KERNEL_INSTALL_TARGET=y
 # BR2_LINUX_KERNEL_NEEDS_HOST_OPENSSL is not set
 # BR2_LINUX_KERNEL_NEEDS_HOST_LIBELF is not set
 # BR2_LINUX_KERNEL_NEEDS_HOST_PAHOLE is not set
@@ -4657,18 +4657,7 @@ BR2_PACKAGE_VIM_RUNTIME=y
 # BR2_TARGET_ROOTFS_AXFS is not set
 # BR2_TARGET_ROOTFS_BTRFS is not set
 # BR2_TARGET_ROOTFS_CLOOP is not set
-BR2_TARGET_ROOTFS_CPIO=y
-BR2_TARGET_ROOTFS_CPIO_FULL=y
-# BR2_TARGET_ROOTFS_CPIO_DRACUT is not set
-BR2_TARGET_ROOTFS_CPIO_NONE=y
-# BR2_TARGET_ROOTFS_CPIO_GZIP is not set
-# BR2_TARGET_ROOTFS_CPIO_BZIP2 is not set
-# BR2_TARGET_ROOTFS_CPIO_LZ4 is not set
-# BR2_TARGET_ROOTFS_CPIO_LZMA is not set
-# BR2_TARGET_ROOTFS_CPIO_LZO is not set
-# BR2_TARGET_ROOTFS_CPIO_XZ is not set
-# BR2_TARGET_ROOTFS_CPIO_ZSTD is not set
-# BR2_TARGET_ROOTFS_CPIO_UIMAGE is not set
+# BR2_TARGET_ROOTFS_CPIO is not set
 # BR2_TARGET_ROOTFS_CRAMFS is not set
 # BR2_TARGET_ROOTFS_EROFS is not set
 BR2_TARGET_ROOTFS_EXT2=y
@@ -4696,7 +4685,8 @@ BR2_TARGET_ROOTFS_ISO9660=y
 BR2_TARGET_ROOTFS_ISO9660_GRUB2=y
 BR2_TARGET_ROOTFS_ISO9660_BIOS_BOOTLOADER=y
 BR2_TARGET_ROOTFS_ISO9660_BOOT_MENU="fs/iso9660/grub.cfg"
-BR2_TARGET_ROOTFS_ISO9660_INITRD=y
+# BR2_TARGET_ROOTFS_ISO9660_INITRD is not set
+# BR2_TARGET_ROOTFS_ISO9660_TRANSPARENT_COMPRESSION is not set
 # BR2_TARGET_ROOTFS_JFFS2 is not set
 # BR2_TARGET_ROOTFS_OCI is not set
 # BR2_TARGET_ROOTFS_SQUASHFS is not set

board/mentalnet/linux-slim.config

@@ -0,0 +1,140 @@
+# Mentalnet GNU/Linux kernel slim-down for the i586 live CD
+# Applied over arch/x86/configs/i386_defconfig via
+# BR2_LINUX_KERNEL_CONFIG_FRAGMENT_FILES
+#
+# Target hardware: 90s Pentium-class PCI machines (TTY-only distro)
+
+# --- NICs: keep only the classic PCI set ---
+CONFIG_NET_VENDOR_8390=y
+CONFIG_NE2K_PCI=y
+CONFIG_NET_VENDOR_INTEL=y
+CONFIG_E100=y
+CONFIG_E1000=y
+CONFIG_E1000E=y
+CONFIG_NET_VENDOR_REALTEK=y
+CONFIG_8139TOO=y
+CONFIG_NET_VENDOR_3COM=y
+CONFIG_NET_VENDOR_DEC=y
+# NB: in kernels >= 6.x the whole 8390/NE2000 family (incl. NE2K_PCI)
+# lives under NET_VENDOR_NATSEMI, so this menu must stay enabled.
+CONFIG_NET_VENDOR_NATSEMI=y
+
+# --- Boot-critical storage/filesystems ---
+CONFIG_SCSI=y
+CONFIG_BLK_DEV_SD=y
+CONFIG_BLK_DEV_SR=y
+CONFIG_ATA=y
+CONFIG_ATA_PIIX=y
+CONFIG_ISO9660_FS=y
+CONFIG_EXT4_FS=y
+
+# --- USB (HID + storage) ---
+CONFIG_USB_SUPPORT=y
+CONFIG_USB=y
+CONFIG_USB_EHCI_HCD=y
+CONFIG_USB_OHCI_HCD=y
+CONFIG_USB_UHCI_HCD=y
+CONFIG_USB_HID=y
+CONFIG_USB_STORAGE=y
+
+# --- Console and serial ---
+CONFIG_SERIAL_8250=y
+CONFIG_SERIAL_8250_CONSOLE=y
+CONFIG_VGA_CONSOLE=y
+
+# --- Drop: wireless stack (no WLAN drivers in use) ---
+# CONFIG_CFG80211 is not set
+# CONFIG_MAC80211 is not set
+
+# --- Drop: SCSI low-level drivers (aic7xxx, SAS, megaRAID, ...) ---
+# CONFIG_SCSI_LOWLEVEL is not set
+
+# --- Drop: RAID and device-mapper ---
+# CONFIG_MD is not set
+
+# --- Drop: sound ---
+# CONFIG_SOUND is not set
+# CONFIG_SND is not set
+
+# --- Drop: graphics accelerators (VGA text console stays via vgacon) ---
+# CONFIG_DRM is not set
+# CONFIG_AGP is not set
+
+# --- Drop: PCMCIA (PCI-only target) ---
+# CONFIG_PCMCIA is not set
+
+# --- Drop: debug/profiling ---
+# CONFIG_KPROBES is not set
+# CONFIG_DEBUG_KERNEL is not set
+# CONFIG_FTRACE is not set
+
+# --- Drop: swap ---
+# CONFIG_SWAP is not set
+
+# --- Drop: all other PCI NIC vendors ---
+# CONFIG_NET_VENDOR_ADAPTEC is not set
+# CONFIG_NET_VENDOR_AGERE is not set
+# CONFIG_NET_VENDOR_ALACRITECH is not set
+# CONFIG_NET_VENDOR_ALTEON is not set
+# CONFIG_NET_VENDOR_AMAZON is not set
+# CONFIG_NET_VENDOR_AMD is not set
+# CONFIG_NET_VENDOR_AQUANTIA is not set
+# CONFIG_NET_VENDOR_ARC is not set
+# CONFIG_NET_VENDOR_ASIX is not set
+# CONFIG_NET_VENDOR_ATHEROS is not set
+# CONFIG_NET_VENDOR_BROADCOM is not set
+# CONFIG_NET_VENDOR_BROCADE is not set
+# CONFIG_NET_VENDOR_CADENCE is not set
+# CONFIG_NET_VENDOR_CAVIUM is not set
+# CONFIG_NET_VENDOR_CHELSIO is not set
+# CONFIG_NET_VENDOR_CISCO is not set
+# CONFIG_NET_VENDOR_CORTINA is not set
+# CONFIG_NET_VENDOR_DAVICOM is not set
+# CONFIG_NET_VENDOR_DLINK is not set
+# CONFIG_NET_VENDOR_EMULEX is not set
+# CONFIG_NET_VENDOR_ENGLEDER is not set
+# CONFIG_NET_VENDOR_EZCHIP is not set
+# CONFIG_NET_VENDOR_FUJITSU is not set
+# CONFIG_NET_VENDOR_FUNGIBLE is not set
+# CONFIG_NET_VENDOR_GOOGLE is not set
+# CONFIG_NET_VENDOR_HUAWEI is not set
+# CONFIG_NET_VENDOR_I825XX is not set
+# CONFIG_NET_VENDOR_LITEX is not set
+# CONFIG_NET_VENDOR_MARVELL is not set
+# CONFIG_NET_VENDOR_MELLANOX is not set
+# CONFIG_NET_VENDOR_META is not set
+# CONFIG_NET_VENDOR_MICREL is not set
+# CONFIG_NET_VENDOR_MICROCHIP is not set
+# CONFIG_NET_VENDOR_MICROSEMI is not set
+# CONFIG_NET_VENDOR_MICROSOFT is not set
+# CONFIG_NET_VENDOR_MYRI is not set
+# CONFIG_NET_VENDOR_NETERION is not set
+# CONFIG_NET_VENDOR_NETRONOME is not set
+# CONFIG_NET_VENDOR_NI is not set
+# CONFIG_NET_VENDOR_NVIDIA is not set
+# CONFIG_NET_VENDOR_OKI is not set
+# CONFIG_NET_VENDOR_PACKET_ENGINES is not set
+# CONFIG_NET_VENDOR_PENSANDO is not set
+# CONFIG_NET_VENDOR_QLOGIC is not set
+# CONFIG_NET_VENDOR_QUALCOMM is not set
+# CONFIG_NET_VENDOR_RDC is not set
+# CONFIG_NET_VENDOR_RENESAS is not set
+# CONFIG_NET_VENDOR_ROCKER is not set
+# CONFIG_NET_VENDOR_SAMSUNG is not set
+# CONFIG_NET_VENDOR_SEEQ is not set
+# CONFIG_NET_VENDOR_SILAN is not set
+# CONFIG_NET_VENDOR_SIS is not set
+# CONFIG_NET_VENDOR_SMSC is not set
+# CONFIG_NET_VENDOR_SOCIONEXT is not set
+# CONFIG_NET_VENDOR_SOLARFLARE is not set
+# CONFIG_NET_VENDOR_STMICRO is not set
+# CONFIG_NET_VENDOR_SUN is not set
+# CONFIG_NET_VENDOR_SYNOPSYS is not set
+# CONFIG_NET_VENDOR_TEHUTI is not set
+# CONFIG_NET_VENDOR_TI is not set
+# CONFIG_NET_VENDOR_VERTEXCOM is not set
+# CONFIG_NET_VENDOR_VIA is not set
+# CONFIG_NET_VENDOR_WANGXUN is not set
+# CONFIG_NET_VENDOR_WIZNET is not set
+# CONFIG_NET_VENDOR_XILINX is not set
+# CONFIG_NET_VENDOR_XIRCOM is not set

board/mentalnet/overlay/etc/resolv.conf

@@ -0,0 +1 @@
+/tmp/resolv.conf

fs/iso9660/grub.cfg

@@ -4,6 +4,5 @@ set timeout="10"
 menuentry "Mentalnet GNU/Linux" {
     search --no-floppy --set=root --file /boot/bzImage
     linux /boot/bzImage root=/dev/sr0 ro
-    initrd /boot/initrd
 }