Problem booting an Raspberry Pi B+ with recent kernels

[Michael Tuexen]

Dear all,

tyring to compile/install/boot a recent kernel fails at the boot level.
Here is the console output:

U-Boot 2013.01-rc1 (Oct 17 2015 - 00:45:25)

DRAM:  480 MiB
WARNING: Caches not enabled
MMC:   bcm2835_sdhci: 0
reading u-boot.env

** Unable to read "u-boot.env" from mmc0:1 **
Using default environment

In:    serial
Out:   lcd
Err:   lcd
mbox: Timeout waiting for response
bcm2835: Could not set USB power state
Net:   Net Initialization Skipped
No ethernet found.
reading uEnv.txt
** Unable to read file uEnv.txt **
Hit any key to stop autoboot:  0 
Booting from: mmc 0 ubldr
reading ubldr
262248 bytes read in 55694 ms (3.9 KiB/s)
## Starting application at 0x02000094 ...
Consoles: U-Boot console  
Compatible U-Boot API signature found @1db682a8

FreeBSD/armv6 U-Boot loader, Revision 1.2
(root at releng2.nyi.freebsd.org, Sat Oct 17 01:09:56 UTC 2015)

DRAM: 480MB
Number of U-Boot devices: 1
U-Boot env: loaderdev='mmc 0'
Found U-Boot device: disk
  Checking unit=0 slice=<auto> partition=<auto>... good.
/boot/kernel/kernel text=0x58fb98 data=0x555a4+0xe5e9c syms=[0x4+0xc6da0+0x4+0x94793]

Hit [Enter] to boot immediately, or any other key for command prompt.
Booting [/boot/kernel/kernel]...               
Using DTB provided by U-Boot at address 0x100.
Kernel entry at 0x2200180...
Kernel args: (null)
panic: Undefined instruction in kernel.

Uptime: 1s

Please note that
* booting r294694 is fine.
* I'm only updating the kernel, the userland is still at 1100081.

Any idea?

Best regards
Michael