I am porting RT Linux 4.9.7 to a custom board. When u-boot tries to load /boot/dtbs/4.9.7-armv7-rt-x4/ompam3-beagle-xm.dtb, it gets an error of FDT_ERR_BADSTRUCTURE. I have looked at the .dts file and removed stuff that are not on the board, like dvi and still get the error.
I’m thinking that if I can disable the tree load in u-boot and get to a Linux command line that I will be able to debug easier.
Is there an easy way to do that?
Ok. Figured that out. Added dtb=null to uEnv.txt. That got me to the following output. It hangs at Starting kernel. I figure I need some minimal device tree to at least get the I2C for the power chip set up.
U-Boot 2017.03-rc1-dirty (Feb 13 2017 - 15:07:27 -0700)
OMAP3630/3730-GP ES1.2, CPU-OPP2, L3-200MHz, Max CPU Clock 1 GHz
OMAP3 Beagle board + LPDDR/NAND
I2C: ready
DRAM: 256 MiB
NAND: 0 MiB
MMC: OMAP SD/MMC: 0
*** Warning - readenv() failed, using default environment
Beagle xM Rev C
No EEPROM on expansion board
No EEPROM on expansion board
OMAP die ID: 715e00029ff800000156083e0501c01d
Net: usb_ether
Error: usb_ether address not set.
Hit any key to stop autoboot: 0
switch to partitions #0, OK
mmc0 is current device
Scanning mmc 0:1…
switch to partitions #0, OK
mmc0 is current device
SD/MMC found on device 0
Checking for: /uEnv.txt …
Checking for: /boot/uEnv.txt …
62 bytes read in 7 ms (7.8 KiB/s)
Loaded environment from /boot/uEnv.txt
Using: dtb=null …
Checking if uname_r is set in /boot/uEnv.txt…
Running uname_boot …
loading /boot/vmlinuz-4.9.7-armv7-rt-x4 …
6435000 bytes read in 499 ms (12.3 MiB/s)
unable to find null …
booting legacy …
debug: [console=ttyO2,115200n8 root=PARTUUID=00000000-02 ro rootfstype=ext4 rootwait] …
debug: [bootz 0x82000000] …
Starting kernel …