Mihai Daniel 
Hi, I'm trying to setup a ramdisk for a setup I have with AT91SAM9261 and 2.6.30 kernel. I know you would say why don't I use initramfs? I will use also that one, as of now I would like to check if I can boot with a ramdisk as rootfs. I have already a root fs running fine on this system in jffs2 format. I used below tutorial: http://www.ibm.com/developerworks/library/l-initrd/ So I created the ramdisk directly on the embedded target, with 4MB size. I used "dd" and "mkefs" and the ramdisk image works fine if I mount it as loop when rootfs is my jffs2. I can browse mount_point and do stuff inside. The content was created according to the section "Manually building initial RAM disk" in the above link. In /dev I placed null and console, in /bin I copied busybox and created the links. I set the execute attribute to init script as well, which works fine when I run it here (as loop device with jffs2 as rootfs) In my kernel config I enabled ramdisk support as follows: CONFIG_BLK_DEV_INITRD=y CONFIG_RD_GZIP=y CONFIG_BLK_DEV_RAM=y CONFIG_BLK_DEV_RAM_COUNT=16 CONFIG_BLK_DEV_RAM_SIZE=4096 Using tftp I download the ramdisk image to 0x21100000. At 0x20008000 I have the kernel uncompressed and at 0x22000000 the zImage copied. However, I'm not able to boot successfully the system as it hangs when checking init process. As I mentioned, I checked several times that my init can be executed, I also used in the bootargs init=/bin/busybox or other scripts/binaries to check if any can be used as init. Command line I use now: > bootargs=64M console=ttyS0,115200 root=/dev/ram0 rw > initrd=0x21100000,4194304 init=/init For some I set ownership to "nobody" just to check if it makes any difference. As it can be seen in the log output the ramdisk is mounted, but init fails. It gives a warning to check the ext2 image, which I did before copying it and I have no error reported. The tftp server is on Windows7. I though I might have some incompatibility if I copy the ramdisk image from linux to Windows then do tftp from Windows server. So I copied the image again from Windows to linux, mounted it and checked if the FS reports any error and scripts can be executed - everything looks normal. So I do have all files in place, attributes set, ramdisk is reported as being mounted ok as rootfs, but init cannot be found. Uncompressing Linux........................................................................... .............................. done, booting the kernel. Linux version 2.6.30-olimex (mishu@KubuntuVM) (gcc version 4.3.3 (Sourcery G++ Lite 2009q1-203) ) #1 Mon Dec 29 13:53:54 CET 2014 CPU: ARM926EJ-S [41069265] revision 5 (ARMv5TEJ), cr=00053177 CPU: VIVT data cache, VIVT instruction cache Machine: Olimex SAM9-L9261 Ignoring unrecognised tag 0x54410008 Memory policy: ECC disabled, Data cache writeback Clocks: CPU 198 MHz, master 99 MHz, main 18.432 MHz Built 1 zonelists in Zone order, mobility grouping on. Total pages: 16256 Kernel command line: 64M console=ttyS0,115200 root=/dev/ram0 rw initrd=0x21100000,4194304 init=/init NR_IRQS:192 AT91: 96 gpio irqs in 3 banks PID hash table entries: 256 (order: 8, 1024 bytes) Console: colour dummy device 80x30 console [ttyS0] enabled Dentry cache hash table entries: 8192 (order: 3, 32768 bytes) Inode-cache hash table entries: 4096 (order: 2, 16384 bytes) Memory: 64MB = 64MB total Memory: 57384KB available (2924K code, 246K data, 132K init, 0K highmem) Calibrating delay loop... 99.12 BogoMIPS (lpj=495616) Mount-cache hash table entries: 512 CPU: Testing write buffer coherency: ok net_namespace: 716 bytes NET: Registered protocol family 16 AT91: Power Management AT91: Starting after user reset bio: create slab <bio-0> at 0 SCSI subsystem initialized usbcore: registered new interface driver usbfs usbcore: registered new interface driver hub usbcore: registered new device driver usb NET: Registered protocol family 2 IP route cache hash table entries: 1024 (order: 0, 4096 bytes) TCP established hash table entries: 2048 (order: 2, 16384 bytes) TCP bind hash table entries: 2048 (order: 1, 8192 bytes) TCP: Hash tables configured (established 2048 bind 2048) TCP reno registered NET: Registered protocol family 1 Trying to unpack rootfs image as initramfs... rootfs image is not initramfs (junk in compressed archive); looks like an initrd Freeing initrd memory: 4096K NetWinder Floating Point Emulator V0.97 (double precision) JFFS2 version 2.2. (NAND) (SUMMARY) © 2001-2006 Red Hat, Inc. msgmni has been set to 120 io scheduler noop registered io scheduler anticipatory registered (default) atmel_lcdfb atmel_lcdfb.0: backlight control is not available atmel_lcdfb atmel_lcdfb.0: 225KiB frame buffer at 23140000 (mapped at ffc00000) Console: switching to colour frame buffer device 40x30 atmel_lcdfb atmel_lcdfb.0: fb0: Atmel LCDC at 0x00600000 (mapped at c4866000), irq 21 atmel_usart.0: ttyS0 at MMIO 0xfefff200 (irq = 1) is a ATMEL_SERIAL atmel_usart.1: ttyS1 at MMIO 0xfffb0000 (irq = 6) is a ATMEL_SERIAL brd: module loaded loop: module loaded ssc ssc.1: Atmel SSC device at 0xc4878000 (irq 15) Driver 'sd' needs updating - please use bus_type methods dm9000 Ethernet Driver, V1.31 eth0 (dm9000): not using net_device_ops yet eth0: dm9000e at c486a000,c486e044 IRQ 107 MAC: 3a:1f:34:08:54:64 (chip) NAND device: Manufacturer ID: 0xec, Chip ID: 0xdc (Samsung NAND 512MiB 3,3V 8-bit) Scanning device for bad blocks Bad eraseblock 1478 at 0x00000b8c0000 Creating 2 MTD partitions on "atmel_nand": 0x000000000000-0x000000040000 : "Partition 1" 0x000000040000-0x000020000000 : "Partition 2" atmel_spi atmel_spi.0: Atmel SPI Controller at 0xfffc8000 (irq 12) ohci_hcd: USB 1.1 'Open' Host Controller (OHCI) Driver at91_ohci at91_ohci: AT91 OHCI at91_ohci at91_ohci: new USB bus registered, assigned bus number 1 at91_ohci at91_ohci: irq 20, io mem 0x00500000 usb usb1: New USB device found, idVendor=1d6b, idProduct=0001 usb usb1: New USB device strings: Mfr=3, Product=2, SerialNumber=1 usb usb1: Product: AT91 OHCI usb usb1: Manufacturer: Linux 2.6.30-olimex ohci_hcd usb usb1: SerialNumber: at91 usb usb1: configuration #1 chosen from 1 choice hub 1-0:1.0: USB hub found hub 1-0:1.0: 2 ports detected Initializing USB Mass Storage driver... usbcore: registered new interface driver usb-storage USB Mass Storage support registered. udc: at91_udc version 3 May 2006 g_serial gadget: Gadget Serial v2.4 g_serial gadget: g_serial ready mice: PS/2 mouse device common for all mice input: gpio-keys as /class/input/input0 ads7846 spi0.2: touchscreen, irq 29 input: ADS784x Touchscreen as /class/input/input1 rtc-at91sam9 at91_rtt.0: rtc core: registered at91_rtt as rtc0 IRQ 1/rtc0: IRQF_DISABLED is not guaranteed on shared IRQs rtc-at91sam9 at91_rtt.0: rtc0: SET TIME! i2c /dev entries driver i2c-gpio: probe of i2c-gpio failed with error -16 Registered led device: led1 Registered led device: led2 Registered led device: led3 Advanced Linux Sound Architecture Driver Version 1.0.20. at73c213 spi0.3: at73c213: supported bitrate is 48500 (64 divider) usb 1-1: new full speed USB device using at91_ohci and address 2 usb 1-1: New USB device found, idVendor=0457, idProduct=0151 usb 1-1: New USB device strings: Mfr=0, Product=2, SerialNumber=3 usb 1-1: Product: USB Mass Storage Device usb 1-1: SerialNumber: 8d54bd8186b42c usb 1-1: configuration #1 chosen from 1 choice scsi0 : SCSI emulation for USB Mass Storage devices ALSA device list: #0: SAM9-L9261 external DAC on irq 15 TCP cubic registered NET: Registered protocol family 17 RPC: Registered udp transport module. RPC: Registered tcp transport module. rtc-at91sam9 at91_rtt.0: hctosys: unable to read the hardware clock RAMDISK: ext2 filesystem found at block 0 RAMDISK: Loading 4096KiB [1 disk] into ram disk... done. EXT2-fs warning: mounting unchecked fs, running e2fsck is recommended VFS: Mounted root (ext2 filesystem) on device 1:0. Freeing init memory: 132K Failed to execute /init. Attempting defaults... Kernel panic - not syncing: No init found. Try passing init= option to kernel. [<c002f414>] (unwind_backtrace+0x0/0xdc) from [<c025bd34>] (panic+0x40/0x110) [<c025bd34>] (panic+0x40/0x110) from [<c0029500>] (init_post+0xd0/0xf8) [<c0029500>] (init_post+0xd0/0xf8) from [<c00085a0>] (kernel_init+0xbc/0xe4) [<c00085a0>] (kernel_init+0xbc/0xe4) from [<c0041998>] (do_exit+0x0/0x5ac) [<c0041998>] (do_exit+0x0/0x5ac) from [<00000001>] (0x1) I plan to rebuild busybox and try again, but as my current ramdisk image works when I mount it as loop I don't have too much confidence it will change something. I'm out of ideas. I've been trying the whole day to get this working. Help is much appreciated. Thanks.