Hi there!
I'm using a customized qemu-4.0.0 with SOC RT3352 (implemented by
Firmguide) in order to emulate D-Link DIR-615 firmware. Using an openwrt file I got a dtb file and compiled qemu
successfully. But when I'm trying to emulate the firmware, I'm not able to identify the right mapping for my FS image file. I used two different squashfs files, one extracted from stock firmware and the other from openwrt lede-17.01.7 image. In both cases I got the same error. The following are the command syntax used.
/tmp/qemu-4.0.0/mipsel-softmmu/qemu-system-mipsel \
-D /dev/null \
-M fg_DIR_615_H1_ralink_rt3352_soc \
-kernel /home/fenix/firmguide/_lede-17.01.7-ramips-rt305x-dir-615-h1-squashfs-sysupgrade.bin.extracted/0.uimage \
-dtb /home/fenix/firmguide/_lede-17.01.7-ramips-rt305x-dir-615-h1-squashfs-sysupgrade.bin.extracted/_40.extracted/410.dtb,offset=0x410 \
-nographic \
-drive file=/tmp/dir-615_H1/lede-17.01.7_dir-615.squashfs,if=none,format=raw \
-append "root=/dev/vda"
I used: vda, vda1, sda, sda1.
Piece of log:
[ 1.544687] rt2880_wdt 10000120.watchdog: Initialized
[ 1.546636] NET: Registered protocol family 10
[ 1.558513] NET: Registered protocol family 17
[ 1.559810] bridge: automatic filtering via arp/ip/ip6tables has been deprecated. Update your scripts to load br_netfilter if you need this.
[ 1.560308] 8021q: 802.1Q VLAN Support v1.8
[ 1.564650] fdt: not creating '/sys/firmware/fdt': CRC check failed
[ 1.579213] VFS: Cannot open root device "vda" or unknown-block(0,0): error -6
[ 1.579566] Please append a correct "root=" boot option; here are the available partitions:
[ 1.580137] Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block(0,0)
[ 1.582285] Rebooting in 1 seconds..
[ 3.551589] Reboot failed -- System halted
But if instead of -drive I use -initrd the emulation runs successfully.
-initrd 0.cpio \
-append "console=ttyS0 nowatchdog nokaslr"
O also tried to create a cpio file from the squashfs files, but I got the same error 'cannot open root device...'.
Thank you !