Can I disable loading of device tree at boot?

[Todd Peterson]

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?

--

John 3:16

IN GOD WE TRUST!!!

[acheesehead]

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 ...