How to install the new kernel image?

[Tom Ivar Helbekkmo <tih%hamartun.priv.no@localhost>]

I've got a Raspberry Pi unit, running a locally built NetBSD 8.99.1
image from October (dmesg.boot attached).  I've just tried updating to a
current kernel, and since the build produces a "netbsd.img" file, I
figured I could just install that as /boot/kernel.img.  That didn't
work, though -- the Pi doesn't even try to boot, but leaves the monitor
with a pretty rainbow-colored test image.

Is there something new that I've missed?

-tih

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    2006, 2007, 2008, 2009, 2010, 2011, 2012, 2013, 2014, 2015, 2016, 2017
    The NetBSD Foundation, Inc.  All rights reserved.
Copyright (c) 1982, 1986, 1989, 1991, 1993
    The Regents of the University of California.  All rights reserved.

NetBSD 8.99.1 (OTIUM) #1: Mon Oct  9 11:20:09 CEST 2017
	root%barsoom.hamartun.priv.no@localhost:/usr/obj/sys/arch/evbarm/compile.evbarm/OTIUM
total memory = 448 MB
avail memory = 435 MB
sysctl_createv: sysctl_create(machine_arch) returned 17
timecounter: Timecounters tick every 10.000 msec
mainbus0 (root)
cpu0 at mainbus0 core 0: 700 MHz ARM1176JZ-S r0p7 (ARM11J V6ZK core)
cpu0: DC enabled IC enabled WB enabled LABT
cpu0: 16KB/32B 4-way L1 VIPT Instruction cache
cpu0: 16KB/32B 4-way write-back-locking-C L1 VIPT Data cache
vfp0 at cpu0: VFP11, rounding, exceptions
obio0 at mainbus0
bcmicu0 at obio0
bcmmbox0 at obio0 intr 65: VC mailbox
vcmbox0 at bcmmbox0
bcmtmr0 at obio0 intr 3: VC System Timer
vchiq0 at obio0 intr 66: BCM2835 VCHIQ
bcmpm0 at obio0: Power management, Reset and Watchdog controller
bcmdmac0 at obio0: DMA0 DMA2 DMA4 DMA5 DMA8 DMA9 DMA10
bcmrng0 at obio0: RNG
plcom0 at obio0 intr 57
plcom0: txfifo disabled
plcom0: console
genfb0 at obio0no data for est. mode 640x480x67
: switching to framebuffer console
genfb0: framebuffer at 0x1c006000, size 1680x1050, depth 32, stride 6720
wsdisplay0 at genfb0 kbdmux 1: console (default, vt100 emulation)
wsmux1: connecting to wsdisplay0
wsdisplay0: screen 1-3 added (default, vt100 emulation)
sdhc0 at obio0 intr 62: SDHC controller
sdhc0: interrupting on intr 62
dwctwo0 at obio0 intr 9: USB controller
bcmspi0 at obio0 intr 54: SPI
spi0 at bcmspi0: SPI bus
bsciic0 at obio0 intr 53: BSC0
iic0 at bsciic0: I2C bus
bsciic1 at obio0 intr 53: BSC1
iic1 at bsciic1: I2C bus
bcmgpio0 at obio0: GPIO [0...31]
gpio0 at bcmgpio0: 32 pins
bcmgpio1 at obio0: GPIO [32...53]
gpio1 at bcmgpio1: 22 pins
bcmcm at obio0 not configured
bcmpwm at obio0 not configured
usb0 at dwctwo0: USB revision 2.0
timecounter: Timecounter "clockinterrupt" frequency 100 Hz quality 0
timecounter: Timecounter "bcmtmr0" frequency 1000000 Hz quality 100
sdhc0: SDHC 3.0, rev 153, platform DMA, 250000 kHz, HS 3.3V, re-tuning mode 1, 1024 byte blocks
sdmmc0 at sdhc0 slot 0
uhub0 at usb0: vendor 0000 (0000) DWC2 root hub (0000), class 9/0, rev 2.00/1.00, addr 1
uhub0: 1 port with 1 removable, self powered
IPsec: Initialized Security Association Processing.
sdmmc0: SD card status: 4-bit, C4
ld0 at sdmmc0: <0x03:0x5344:SU16G:0x80:0x119b36bc:0x0b9>
ld0: 15193 MB, 7717 cyl, 64 head, 63 sec, 512 bytes/sect x 31116288 sectors
ld0: 4-bit width, High-Speed/SDR25, 50.000 MHz
uhub1 at uhub0 port 1: vendor 0424 (0x424) product 9514 (0x9514), class 9/0, rev 2.00/2.00, addr 2
uhub1: multiple transaction translators
uhub1: 5 ports with 4 removable, self powered
usmsc0 at uhub1 port 1
usmsc0: vendor 0424 (0x424) product ec00 (0xec00), rev 2.00/2.00, addr 3
usmsc0: Ethernet address b8:27:eb:ff:51:2a
ukphy0 at usmsc0 phy 1: OUI 0x00800f, model 0x000c, rev. 3
ukphy0: 10baseT, 10baseT-FDX, 100baseTX, 100baseTX-FDX, auto
uhub0: illegal enable change, port 1
WARNING: 1 error while detecting hardware; check system log.
boot device: ld0
root on ld0a dumps on ld0b
/: replaying log to memory
root file system type: ffs
kern.module.path=/stand/evbarm/8.99.1/modules
vchiq: vchiq_init_state: slot_zero = 0xc9710000, is_master = 0
vchiq: local ver 8 (min 3), remote ver 8.
vcaudio0 at vchiq0: auds
WARNING: no TOD clock present
WARNING: using filesystem time
WARNING: CHECK AND RESET THE DATE!
audio0 at vcaudio0: half duplex, playback, capture, mmap, independent
vcaudio0: Virtual format configured - Format SLINEAR, precision 16, channels 2, frequency 48000
spkr0 at audio0: PC Speaker (synthesized)
wsbell at spkr0 not configured
/: replaying log to disk
wsdisplay0: screen 4 added (default, vt100 emulation)
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