I have 1 desktop that won't properly boot chimaera.  This is a machine I used once a week.
It ran beowulf fine (I may just go back to that).
I updated the apt sources to chimaera, did the upgrade and dist-upgrade successfully.  Rebooted into chimaera okay.
Some time later (the next week?) it wouldn't complete the boot -- it would go so far and then reboot itself (stuck in a reboot-loop).
I was able to boot into an older kernel, and it started up okay.
The following week, same problem.  Only the older kernel wouldn't complete its boot either.  I went to recovery mode, and was able to log in, exited and GUI started up fine.
The following week, nothing I did was successful.  Even "recovery mode" does not complete far enough to get me to login -- it reboots and reboots and reboots!  I let it continue this for over a half hour before shutting it down.

I've replaced this desktop with another one, so a fix is not something that is urgent or even necessary.  I have noticed, in attempts to get it working, that it will successfully boot jessie desktop-live USB; but will not even boot up from chimaera desktop-live USB (it does the reboot thing).
Perhaps there is some incompatible hardware ... but if that's the case I am confused why it initially worked after the dist-upgrade.  Should I just go back to beowulf?
I don't even know where to start looking for the cause ... syslog ?  kern.log ?  record a video of the boot to get the last message before it reboots ?
The chimaera desktop-live USB does work on other hardware so I don't think that it is a problem, either.

An old inxi output (showing the correct hardware at least; other info may be outdated)

System:
  Host: fcc-audio Kernel: 5.8.0-0.bpo.2-amd64 x86_64 bits: 64 compiler: N/A 
  Desktop: Xfce 4.12.4 tk: Gtk 2.24.32 info: xfce4-panel wm: xfwm4 
  dm: SLiM 1.3.6 Distro: Devuan GNU/Linux 3 (beowulf) 
Machine:
  Type: Desktop Mobo: MSI model: FM2-A55M-E33 (MS-7721) v: 2.0 serial: N/A 
  BIOS: American Megatrends v: 11.6 date: 02/12/2015 
CPU:
  Topology: Quad Core model: AMD A10-6800K APU with Radeon HD Graphics 
  bits: 64 type: MCP arch: Piledriver rev: 1 L1 cache: 192 KiB 
  L2 cache: 2048 KiB 
  flags: lm nx pae sse sse2 sse3 sse4_1 sse4_2 sse4a ssse3 svm 
  bogomips: 32736 
  Speed: 1993 MHz min/max: 2000/4100 MHz boost: enabled Core speeds (MHz): 
  1: 1996 2: 1996 3: 2092 4: 2044 
Graphics:
  Device-1: AMD Richland [Radeon HD 8670D] vendor: Micro-Star MSI 
  driver: radeon v: kernel bus ID: 00:01.0 chip ID: 1002:990c 
  Display: server: X.Org 1.20.4 driver: ati,radeon 
  unloaded: fbdev,modesetting,vesa resolution: 1024x768~60Hz 
  OpenGL: renderer: AMD ARUBA (DRM 2.50.0 / 5.8.0-0.bpo.2-amd64 LLVM 7.0.1) 
  v: 4.3 Mesa 18.3.6 compat-v: 3.1 direct render: Yes 
Audio:
  Device-1: AMD Trinity HDMI Audio vendor: Micro-Star MSI 
  driver: snd_hda_intel v: kernel bus ID: 00:01.1 chip ID: 1002:9902 
  Device-2: AMD FCH Azalia vendor: Micro-Star MSI driver: snd_hda_intel 
  v: kernel bus ID: 00:14.2 chip ID: 1022:780d 
  Sound Server: ALSA v: k5.8.0-0.bpo.2-amd64 
Network:
  Device-1: Realtek RTL8111/8168/8411 PCI Express Gigabit Ethernet 
  vendor: Micro-Star MSI driver: r8169 v: kernel port: e000 bus ID: 01:00.0 
  chip ID: 10ec:8168 
  IF: eth0 state: down mac: xx:xx:xx:xx:xx:xx 
Drives:
  Local Storage: total: 88.98 GiB used: 22.56 GiB (25.4%) 
  ID-1: /dev/sda vendor: Western Digital model: WD800JD-60LSA5 
  size: 74.53 GiB speed: 3.0 Gb/s serial: WD-XXXXXXXXXXXX rev: 1E03 
  temp: 35 C scheme: MBR 
  ID-2: /dev/sdf type: USB vendor: Toshiba model: TransMemory 
  size: 14.45 GiB serial: XXXXXXXXXXXXXXXXXXXXXXXX rev: 1.00 scheme: MBR 
Partition:
  ID-1: / size: 21.88 GiB used: 8.81 GiB (40.3%) fs: ext4 dev: /dev/sda2 
  ID-2: /boot size: 938.0 MiB used: 177.7 MiB (18.9%) fs: ext2 
  dev: /dev/sda1 
  ID-3: /home size: 41.92 GiB used: 6.25 GiB (14.9%) fs: ext4 dev: /dev/sda3 
  ID-4: swap-1 size: 8.41 GiB used: 0 KiB (0.0%) fs: swap dev: /dev/sda4 
Sensors:
  System Temperatures: cpu: 10.8 C mobo: N/A gpu: radeon temp: 0 C 
  Fan Speeds (RPM): N/A 
Info:
  Processes: 162 Uptime: 1h 48m Memory: 7.06 GiB used: 725.2 MiB (10.0%) 
  Init: SysVinit v: 2.93 runlevel: 2 default: 2 Compilers: gcc: 8.3.0 
  alt: 6/8 Shell: bash (sudo) v: 5.0.3 running in: xfce4-terminal 
  inxi: 3.0.32 

I was recently given an old imac computer.  It was running a very old mac os 10.6 and would not install a newer version.  So I've decided to put devuan on it.
The CPU (an Intel Core 2 Duo) is indeed 64-bit capable.  However, the computer refuses to boot devuan amd64 dvds.  I've tried both ascii and beowulf, full desktop and netinstall; tried from both the internal drive and an external drive.  It will not boot from these discs.  What I have been able to do so far, is install from the i686 disc, then install an amd64 kernel and boot from it.  I've been unable, at this point, to change all of the system packages over to amd64.  I can mount and read the amd64 desktop installer dvd, but can't seem to start the installer from there without booting from it (?)   I mainly want to use amd64 since it's required for most modern web browsers (most seemed to stop updating 32-bit versions several years ago).  Any advice?   I've read a few different "cross-grading" articles, but so far I've only managed to break apt/dpkg.

In Jessie this worked:
/usr/bin/xfce4-session-logout --suspend

before suspending, the system would call
/etc/pm.d/sleep/50_unmount
which I have unmount certain things...

Now in Ascii, the /etc/pm.d/sleep/50_unmount is no longer called when suspending.
In fact, none of the files in /etc/pm.d/sleep are called when resuming from suspend, either.
Is this a bug or intentional change, or do I have something else misconfigured?

I can work around this, but just wondering what has changed or if /etc/pm.d/sleep/* has been abandoned for some other way of calling scripts on suspend/hibernate/thaw/resume.