I built Linux RT for a custom board based upon Beagleboard xM exactly as in Robert C. Nelson's page
.
Here is what I get during boot, tried on a real Beagleboard xM and get the same behavior. The booting stops at a u-boot prompt.
U-Boot SPL 2017.03-rc1-dirty (Feb 04 2017 - 12:10:18)
Trying to boot from MMC1
SPL: Please implement spl_start_uboot() for your board
SPL: Direct Linux boot not active!
reading u-boot.img
reading u-boot.img
U-Boot 2017.03-rc1-dirty (Feb 04 2017 - 12:10:18 -0700)
OMAP3630/3730-GP ES1.2, CPU-OPP2, L3-200MHz, Max CPU Clock 1 GHz
OMAP3 Beagle board + LPDDR/NAND
I2C: ready
DRAM: 512 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: 101000229ff80000016830c319017022
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 ...
26 bytes read in 7 ms (2.9 KiB/s)
Loaded environment from /boot/uEnv.txt
Checking if uname_r is set in /boot/uEnv.txt...
Running uname_boot ...
** Invalid partition 3 **
** Invalid partition 4 **
** Invalid partition 5 **
** Invalid partition 6 **
** Invalid partition 7 **
=>