Need help with BeagleBoard rev. C4

[Stefan Hertenberger <Stefan@Hertenberger.bayern>]

Hello,

i think i need some help setting up my beagleboard rev C4. I found
instructions to build a linux SD on this wiki
https://eewiki.net/display/linuxonarm/BeagleBoard, so i decided to
update u-boot and try linux. Without success, the system stops at

Starting kernel ...

then i downloaded the latest NetBSD current image for beagleboard and
tried to boot

U-Boot 2016.09-dirty (Oct 13 2016 - 21:08:39 +0200)   
                                                      
OMAP3530-GP ES3.1, CPU-OPP2, L3-165MHz, Max CPU Clock 720 MHz
OMAP3 Beagle board + LPDDR/NAND
I2C:   ready
DRAM:  256 MiB
NAND:  256 MiB
MMC:   OMAP SD/MMC: 0
Beagle Rev C4
Timed out in wait_for_event: status=0000
Check if pads/pull-ups of bus are properly configured
No EEPROM on expansion board
Timed out in wait_for_event: status=0000
Check if pads/pull-ups of bus are properly configured
No EEPROM on expansion board
OMAP die ID: 6d5800040000000004039ba60802500e
Net:   usb_ether
Error: usb_ether address not set.

Hit any key to stop autoboot:  0 
=> mmc rescan
=> fatload mmc 0 81000000 netbsd-BEAGLEBOARD.ub; bootm 81000000
root=ld0a console=com0


the system starts but fails with

...
omapmputmr0 at obio2 addr 0x49032000-0x490320ff intr 38: OMAP MPU Timer
#2 
omapmputmr1 at obio2 addr 0x49034000-0x490340ff intr 39: OMAP MPU
Timer #3 
omapmputmr2 at obio2 addr 0x49036000-0x490360ff intr 40: OMAP MPU Timer
#4 
clock: hz=100 stathz=64 data_abort_handler: data_aborts fsr=0x1808
far=0xe103401c 
Fatal kernel mode data abort: 'External Non-Linefetch Abort (S)'
trapframe: 0x80afbeb0 FSR=00001808, FAR=e103401c, spsr=20000153
r0 =00000000, r1 =e1034000, r2 =0000001c, r3 =00000000
r4 =8080ff5c, r5 =80acd1b8, r6 =8077ad04, r7 =00000000
r8 =8030e880, r9 =8ef17ed0, r10=87ffc01b, r11=80afbf2c
r12=80afbed0, ssp=80afbf00, slr=80306078, pc =8030e880

Stopped in pid 0.1 (system) at  netbsd:generic_bs_w_4:  str     r3,
[r1, r2]
db> bt
0x80afbf2c: netbsd:cpu_initclocks+0xc
0x80afbf94: netbsd:initclocks+0x48
0x80afbfec: netbsd:main+0x238
0x80afbffc: netbsd:kernel_text+0x50
db>

Is u-boot the cause? any ideas are welcome.

the board seems to work because i can boot an old angstrom linux image
and with the old u-boot, from 2009 even NetBSD was able to boot.

Kind regards
Stefan Hertenberger