List of maker boards

Ever since the Raspberry Pi became popular several new ARM development boards have hit the market, some even predate the Pi but gained more popularity as the Pi paved the way into mainstream. It's getting to the point where it's difficult to keep track of all the new offerings so this post is a reference list for myself which i plan on updating as new interesting devices become available. It only lists hacker friendly mainboards and not ARM devices in general. It would be fun to add some MIPS based boards too - some do exist, but the ARM based devices tend to be more interesting and popular. I list only the models with the highest spec available.

With the performance boost of the Raspberry Pi 2 & 3 most alternative maker boards loose their appeal - but the various outputs or the presence of gigabit ethernet still makes some alternatives into better options. Recently Udoo has caught my attention as a project with interesting ideas and their recent x86 model has great potential for real-world deployment where the Raspberry is too limited - digital signage springs to mind. I've known about Udoo for years but now that their x86 board is on it's way I think it has excellent potential even though it's a lot more expensive than the Pi.

Board	URL	CPU	Cores	GPU	RAM
Raspberry Pi 3	Website	ARM Cortex A53	4@1.2GHz	Broadcom VideoCore IV	1GB
Beagleboard	Website	ARM Cortex A8	1@1GHz	PowerVR SGX530	512MB
Pandaboard	Website	ARM Cortex A9 MPCore	2@1.2GHz	PowerVR SGX540	1GB
ArndaleBoard	Website	ARM Cortex A15	2@1.7GHz	Mali-T604	2GB
Wandboard	Website	Freescale i.MX6 Quad	4@1GHz	Vivante GC 2000	2GB
Udoo	Website	Freescale i.MX6 Quad	4@1GHz	Vivante GC 2000	1GB
HummingBoard	Website	Freescale i.MX6 Quad	4@1GHz	Vivante GC 2000	2GB
pcDuino3	Website	AllWinner A20 (ARM Cortex A7 Dual Core)	2@1GHz	Mali-400MP2 (Dual Core)	1GB
Banana Pi	Website	AllWinner A20 (ARM Cortex A7 Dual Core)	2@1GHz	Mali-400MP2 (Dual Core)	1GB
Cubieboard	Website	AllWinner A20 (ARM Cortex-A7 Dual Core)	2@1GHz	Mali-400MP2 (Dual Core)	2GB
OLinuXino	Website	??	??	??	??
APC Rock	Website	??	??	??	??
Origenboard	Website	??	??	??	??
ODROID	Website	??	??	??	??
CuBox-i	Website	??	??	??	??

I'll keep updating this.

How to force a downgrade of the BIOS on a HP Z Workstation

Important note: I've only done this on a HP Z820 so I cannot guarantee that it's possible on other models.

I ran into a seemingly rare problem when i upgraded to the latest BIOS on my Z820 Workstation - Intel AMT stopped working. I didn't notice this at first so I could only assume the BIOS upgrade screwed things up. My machine originally had a really old original 1.x BIOS on it and I only did one intermediate (and mandatory) BIOS update before I jumped to the very latest version and I think this huge leap between versions might have contributed to the breakage - that along with the fact that I hadn't flashed the latest Intel AMT firmware along with the newer BIOS. To my dismay the HP download page said that BIOS downgrades were no longer allowed and sure enough - you really can't downgrade - not even when flashing from inside the BIOS. It was sloppy of me not to check this beforehand.

So what was I to do? I tried everything I could think of and finally discovered how to get around this and in the end it wasn't even all that difficult, obvious even. You see, HP Z Workstations allows you to bridge some pins on the motherboard to put the machine in emergency recovery mode (look it up in the manual) to rescue the computer from a bad BIOS flash. In emergency recovery mode you bypass the BIOS entirely and use the bootblock to load an old BIOS image from a USB stick - one that doesn't prevent downgrades which then, in turn, allows you to flash any BIOS version. The emergency recovery procedure is well documented. It probably didn't occur to the HP engineers that the bootblock should be able to prevent older BIOS's from loading because that in itself would involve risks if a new and badly flashed BIOS along with the bootblock prevented you from going to an earlier (working) version.

The procedure is as follows:

1. Bridge the emergency recovery pins on motherboard (check manual for instructions).
2. Prepare a USB stick with an older BIOS that doesn't prevent downgrades - this is very important. Only the last couple of versions prevent downgrades so you won't have to go too far back. Changelogs will note if BIOS no longer allows downgrade.
3. Boot your workstation with USB stick connected to a USB port, the emergency recovery mode will now start the computer seemingly like normal - except the older BIOS is now running off your USB stick and not the one flashed to your motherboard. Pay attention during boot to see which BIOS version is loaded as you boot.
4. Download and flash any BIOS version you like once booted into your operating system, effectively downgrading the BIOS.
5. Unbridge pins on motherboard.

As far as I know the BIOS still needs to be a signed, original HP BIOS and I assume the bootblock verifies this. Still, I haven't tried any non-official firmware so I cannot say for sure.

Anyway, Intel AMT started working again with the latest BIOS after I made smaller, incremental, updates between versions and somewhere in between I managed to flash the latest Intel AMT firmware so this little trick solved my problem. I can't remember all the BIOS versions I jumped between to get AMT up and running again but it shouldn't be difficult to figure out - just keep downgrading to older BIOS's until you find one that makes it work again and then do upgrades a bit more carefully - and don't forget to check the device manager to make sure the Intel Management Engine is still working. Regardless of what HP wants you to think you will not break the machine by going from the very latest BIOS to a much older one - older BIOS's worked just fine for me. There are also other reasons you might want to downgrade the BIOS - some applications are certified to run on very specific BIOS versions so this way you can downgrade a new BIOS to one that is certified for an application that requires it. Or maybe a newer version was just unstable? That's something I've experienced on occasion.

HP insist that "you cannot downgrade" but considering that others might run into similar problems I figured this trick could be important to share. What's interesting is that there is no way for HP to actually prevent you from doing this in the future unless they're willing to also update the bootblock and they are notoriously resistant to do this - and for good reason, because it opens up the possibility of permanently bricking a machine in the event of a bad flash of said bootblock. If, however, they did release bootblock updates with version checking many would at the same time rejoice as newer bootblocks would finally allow early revision motherboards to support v2 Xeons, which they technically can do but are not allowed to by the older 2011 bootblock. Still, my guess is that HP will never allow bootblock updates and this also means is that they can never stop you from downgrading the BIOS regardless of what they claim.

HP Z820 Workstation Fan Inventory

I've been considering a complete fan replacement on my HP Z820 Workstation but there are some issues to be aware of. First of all there is a whopping 12 fans in total and HP uses a non-standard OEM pinout, which makes the modifier numbers especially important. The second issue is that different workstation revisions use different fans - some fan shrouds seem to be equipped with Delta fans only while others are a mix of Delta, Nidec and AVC. Surprisingly the model numbers used on individual fans is poorly documented, presumably because owners are expected to buy an entire fan shroud replacement if one or more fans go bad or a kit of front or back facing fans. If the fans go bad on the power supply you are probably meant to get a new one. When you have an expired warranty, options become a bit more limited so I find it far more compelling and cost effective to just buy the individual fans and replace them myself, and to do that you'll need to know exactly what models that work.

My goal here is to - first and foremost - identify all the fans, including their positions, in my own workstation and then all alternatives that can work as drop-in replacements. The HP Z820 seems to be able to use the exact same fans as the newer Z840 and vice versa. A number of these fans should work in the Z600/Z400-series and the older Z800. I cannot confirm this, however, as I don't have a Z800 so my main focus will be on the Z820.

Why bother with this? Delta fans, for example, have a good reputation but are unfortunately known to be noisy so owners with those might be interested in the quieter Nidec options - especially if you do audio work and need a quieter system. Those of us with Nidec fans might be interested in replacing them with Delta's for other reasons - perhaps the better longevity, price and availability are deciding factors. I wanted to document the cooling fans to make things easier for people who want to do the replacement themselves so having the exact model information should keep your workstation within HP's specifications (CFM, RPM etc.). The fan numbering scheme i use in the images is arbitrary. I think information about alternative fans to those i happen to have is somewhat complete but I have no way of knowing if I've identified all variants HP has used in these workstations. I don't have all modifier numbers yet but I will update this post when/if I do.

Update: I went with the option of replacing the entire shroud because the combined shipping costs and rarity of some fans was making things difficult. I got a great deal on eBay on a brand new shroud for the dual cpu option.

The Shroud

The Case

The Powersupply

FAN1, FAN2 & FAN4

  Dimensions: 60mm (Blower-style) 4-pin
  Model: Delta BUB0712HF
  Modifier number: -BE04
  HP P/N: 670051-001 REV 1

FAN3

Note: The AVC fan in my shroud doesn't seem to have a HP product number which suggests that the generic model might have the same pinout. I did manage to find the PN from other sources, however.

  Dimensions: 60*60*25mm 4-pin PWM
  Model: AVC DS06025B12U
  Modifier number: P063
  HP P/N: 670050-001 Rev.A

  Alternative Delta Model
  Dimensions: 60*60*25mm 4-pin PWM
  Model: Delta AFB0612EH
  Modifier number: ??
  HP P/N: ?? (PN Required for HP OEM model)

FAN5, FAN6, FAN9 & FAN10

Note: The Nidec fans are rated at ~38db while Delta's are around ~45-49db and both run at 3800 RPM. Some sources suggest the Nidec fans use sleeve bearings while others that it's a ball bearing - I'm pretty sure they're sleeve bearing. The 92mm Nidec's have a MTBF of 45.000h which is nearly equal to the 50.000h you are likely to get from the Delta. I could not find the specifications for these exact OEM fans so these are my best guesses based on the specifications of the non-OEM equivalents of the Nidec and Delta fans. In other words, I cannot guarantee the above statements about the bearing, MTBF and noise profile to be 100% correct.

  Dimensions: 92*92*25mm 4-pin
  Model: Nidec T92T12MS3A7-57A03
  Modifier number: 2223G
  HP P/N: 647113-001 REVA (or REVB)

  Alternative Delta Model
  Dimensions: 92*92*25mm 4-pin
  Model: Delta QUR0912VH
  Modifier number: -AK59
  HP P/N: 647113-001 REV 0A

  Alternative Nidec Model (New revision that should work)
  Dimensions: 92*92*25mm 4-pin
  Model: Nidec FAN A T92T12MS3A7-57A03
  Modifier number: ??
  HP P/N: 644315-001 REVB

  Alternative Delta Model (Used in Z800 that should work)
  Dimensions: 92*92*25mm 4-pin
  Model: Delta QUR0912VH
  Modifier number: -8C2T
  HP P/N: 468763-001

FAN7 & FAN8

Note: FAN7 & FAN8 come as a pair with wires going to the same proprietary 6-pin connector

  Dimensions: Dual 92*92*25mm fans to one 6-pin
  Model: Nidec FAN B T92T12MS3A7-57A03
  Modifier number: 2429H F4 / 4X30H G4
  HP P/N: 644315-001 REVB

  Alternative Delta Model
  Dimensions: Dual 92*92*25mm fans to one 6-pin
  Model: Delta QUR0912VH
  Modifier number: -BL3H
  HP P/N: 644315-001 REV 0B (or 0A)

FAN11 & FAN12

Note: The powersupply contains two identical Delta fans of the below model, these were found in the 1125W PSU and are likely also to be found in the less powerful 800W PSU. Given that Delta builds these I doubt any other fans models are used.

  Dimensions: 80*80*25mm 4-pin
  Model: Delta QUR0812SH
  Modifier number: -HE00
  HP P/N: None