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by drmacro
Fri Jul 27, 2018 11:49 am
Forum: Troubleshooting
Topic: Image burning fails first time, works second
Replies: 3
Views: 347

Re: Image burning fails first time, works second

Hmm...I think??? I've tried it after un-mounting and the same results.

I'm doing some Iot/mqtt stuff at the moment with multiple pi's, so I think I'll get the chance to "play" with it again. ;)
by drmacro
Wed Jul 25, 2018 1:07 pm
Forum: Troubleshooting
Topic: Image burning fails first time, works second
Replies: 3
Views: 347

Image burning fails first time, works second

Hi, I typically used the following in a terminal window on Ubuntu to burn the rasbian image to a SD card: sudo dd bs=4M if=2018-06-27-raspbian-stretch.img of=/dev/sdb then a sync command. Most of the time, it results in a corrupt SD card that won't boot. But, if I run the exact commands again on the...
by drmacro
Thu Mar 01, 2018 2:59 pm
Forum: Other projects
Topic: Smarti Pi Touch
Replies: 19
Views: 6787

Re: Smarti Pi Touch

I recently put together a plex server using this case and a Pi 3.

I tried the deep back hat cover, but had to remove it because the Pi kept showing the overheat icon.

I have heat sinks on both chips (but, the case covers the smaller one.

Any thoughts?
by drmacro
Tue Apr 25, 2017 2:32 pm
Forum: Advanced users
Topic: Raspbian SD card image
Replies: 4
Views: 699

Re: Raspbian SD card image

I use sync after the write by default. Doesn't make any difference.

And physically ejecting makes no difference.

I suspect it has something to do with the partition table before the dd command. But it is whatever Sandisk ships from the factory.
by drmacro
Mon Apr 24, 2017 11:21 pm
Forum: Advanced users
Topic: Raspbian SD card image
Replies: 4
Views: 699

Raspbian SD card image

I use the following on ubuntu to get a raspbian image to an sd card: sudo dd bs=4M if=2017-04-10-raspbian-jessie.img of=/dev/sdc Works fine unless I'm using a new sd card. In that case, it works the second time. After the first time there the usual 4G root partition with home, bin, etc, root, ... an...
by drmacro
Fri Dec 09, 2016 7:58 pm
Forum: General discussion
Topic: Raspbian with Read-only Root
Replies: 191
Views: 85725

Re: Raspbian with Read-only Root

OK, after some experimentation it does appear root is read only now.

But, other than df showing filesystem for / being overlay, how would I know? (I know I can create something and re-boot to see if its still there...)

(PS: my apologies for all the chatter. :oops: )
by drmacro
Fri Dec 09, 2016 6:03 pm
Forum: General discussion
Topic: Raspbian with Read-only Root
Replies: 191
Views: 85725

Re: Raspbian with Read-only Root

Went back and retraced my steps found a couple of things I missed in overlay. Fixed that and re-ran update-initramfs. Now I see no errors, but mount still shows everything as rw. And, if I create something, say in /home/pi, it's there after re-boot. :( Ok, so I read those lines a few more times and ...
by drmacro
Fri Dec 09, 2016 5:23 pm
Forum: General discussion
Topic: Raspbian with Read-only Root
Replies: 191
Views: 85725

Re: Raspbian with Read-only Root

Ok, so I read those lines a few more times and decided that it was meant that they should be added, I did so.

After boot. dmesg shows: overlayfs: failed to resolve '/upper/data': -2

'mount' shows nothing read only.

:?
by drmacro
Fri Dec 09, 2016 3:56 pm
Forum: General discussion
Topic: Raspbian with Read-only Root
Replies: 191
Views: 85725

Re: Raspbian with Read-only Root

So I proceeded. When editing local_mount_root(), I can see the part that is to be commented out. But the rest of the listing shown in this post is significantly different that the content of my overlay file. Are the differences to be added to my local_mount_root()? I'm guessing yes...but, I'd rather...
by drmacro
Fri Dec 09, 2016 3:49 pm
Forum: General discussion
Topic: Raspbian with Read-only Root
Replies: 191
Views: 85725

Re: Raspbian with Read-only Root

I mentioned in another post, just so it's here: drmacro wrote: Well that looks great, especially since is is with jessie...but in the second set of instructions "cp -rp local-bottom overlay-bottom", get a "no such file or directory" error. Sorry, about that. Please try just skipping that step. Unles...
by drmacro
Fri Dec 09, 2016 3:45 pm
Forum: Raspbian
Topic: Read-only Jessie
Replies: 17
Views: 8654

Re: Read-only Jessie

Well that looks great, especially since is is with jessie...but in the second set of instructions "cp -rp local-bottom overlay-bottom", get a "no such file or directory" error. Sorry, about that. Please try just skipping that step. Unless an important package is missing it should still work. Let me...
by drmacro
Thu Dec 08, 2016 8:08 pm
Forum: Raspbian
Topic: Read-only Jessie
Replies: 17
Views: 8654

Re: Read-only Jessie

Well that looks great, especially since is is with jessie...but

in the second set of instructions "cp -rp local-bottom overlay-bottom", get a "no such file or directory" error.
by drmacro
Thu Dec 08, 2016 7:08 pm
Forum: Raspbian
Topic: Read-only Jessie
Replies: 17
Views: 8654

Re: Read-only Jessie

The various web sites that have documented making the PI read only remove a variety of packages. In addition, they end up making the normal place the seed file gets written, read only. Thus the need to create the seed on each boot in some temp space. At least that is how I understand the random-seed...
by drmacro
Thu Dec 08, 2016 4:07 pm
Forum: Raspbian
Topic: Read-only Jessie
Replies: 17
Views: 8654

Re: Read-only Jessie

That does fix the random-seed error.

But, even with resolv.conf in /tmp dhcpcd fails to start.

using "systemctl status dhcpcd.service" after boot it complains as follows:

dhcp_bind: write_lease: Read-only file system

I tried moving /var/log/dhcpcd to /tmp, same results.
by drmacro
Wed Dec 07, 2016 3:27 pm
Forum: Raspbian
Topic: Read-only Jessie
Replies: 17
Views: 8654

Re: Read-only Jessie

I've been attempting to get a read only system with the latest jessie and a pi 2 B (note: same results with a 3 as well). In addition to the random seed error dhcpcd (the dhcp client daemon) fails to start. Since, typically, there was a dhcp lease available before things were read only, the old leas...
by drmacro
Sat Nov 26, 2016 7:59 pm
Forum: Advanced users
Topic: Read only setup with JESSIE?
Replies: 0
Views: 410

Read only setup with JESSIE?

Hi, Anybody do a read only setup with the latest JESSIE release? I've tried the one here: https://k3a.me/how-to-make-raspberrypi-truly-read-only-reliable-and-trouble-free/ attempted a few additions from here: https://hallard.me/raspberry-pi-read-only/ I've gotten pretty close (read: reduced the numb...
by drmacro
Fri Nov 25, 2016 4:16 pm
Forum: General discussion
Topic: Raspberry Pi A+ Mechanical Drawings???
Replies: 13
Views: 2913

Re: Raspberry Pi A+ Mechanical Drawings???

The old ones are here: http://www.raspiworld.com/viewtopic.php?t=13 http://www.raspiworld.com/images/other/drawings/Raspberry-Pi-1-Model-B.pdf Those are good and provide very accurate hole placement for the mounting holes and their diameters. Unfortunately, there is still a bit of reverse engineeri...
by drmacro
Thu Nov 24, 2016 5:06 pm
Forum: General discussion
Topic: Raspberry Pi A+ Mechanical Drawings???
Replies: 13
Views: 2913

Re: Raspberry Pi A+ Mechanical Drawings???

That's perfect for the 40 pin gpio models. Thanks!

But not the B with 26 pin header.
by drmacro
Thu Nov 24, 2016 3:55 pm
Forum: General discussion
Topic: Raspberry Pi A+ Mechanical Drawings???
Replies: 13
Views: 2913

Re: Raspberry Pi A+ Mechanical Drawings???

Anybody have the same info for a model B? I'm doing a pcb layout for a board that plugs into the GPIO header and need to know to where pin 1 of the 26 pin GPIO connector and the mounting holes all relative to a given point on the board. (using calipers will get close...but, I'd prefer to minimize re...
by drmacro
Thu Oct 13, 2016 5:13 pm
Forum: Device Tree
Topic: Override GPIO state at boot
Replies: 14
Views: 9059

Re: Override GPIO state at boot

Thanks!

Now someday, in my copious spare time, I'll go figure out blobs and trees. ;)

Mac
by drmacro
Thu Oct 13, 2016 5:04 pm
Forum: Device Tree
Topic: Override GPIO state at boot
Replies: 14
Views: 9059

Re: Override GPIO state at boot

So, if I understand correctly: The output of raspi-get lists GPIO##. GPIO## refers to the BCM GPIO number. So, referring to GPIO07 is the same as seen elsewhere as BCM7? And, one needs to take a close look at how these are referred to in the programming language of choice. And, if available as in Py...
by drmacro
Thu Oct 13, 2016 4:21 pm
Forum: Device Tree
Topic: Override GPIO state at boot
Replies: 14
Views: 9059

Re: Override GPIO state at boot

Hmm...interesting, by sheer coincidence the pins I'm using are correct in both charts. (In the linked chart, the pins in the chart I referred to are shown as GPIO_GENx.) It appears whoever made the chart I used totally screwed up everything that was added for the 40 pin header. In any case, after ru...
by drmacro
Thu Oct 13, 2016 2:12 pm
Forum: Device Tree
Topic: Override GPIO state at boot
Replies: 14
Views: 9059

Re: Override GPIO state at boot

The safest (and easiest) way to get a known pin state from power-on is to choose pins which have the correct pull state - work with the system, not against it. By default, GPIOs 0-8 pull high, and GPIOs 9-27 pull low. You can always add an external inverter if you need to. In this case the system d...
by drmacro
Thu Oct 13, 2016 1:30 pm
Forum: Device Tree
Topic: Override GPIO state at boot
Replies: 14
Views: 9059

Re: Override GPIO state at boot

I did some messing around with the dt blob and the dev tree several months back. It was never clear which to use (for a given desired effect) and when either content took effect. (Read everything I could at that point and didn't come away with anything definitive in my mind.) In this application, I'...
by drmacro
Sat Oct 08, 2016 7:39 pm
Forum: Device Tree
Topic: Override GPIO state at boot
Replies: 14
Views: 9059

Override GPIO state at boot

HI, I've read and even participated in some forum threads in the past about being able to force the state of the GPIO pins at boot time. At different points device trees and at another point overlays were the preferred method. Lots of what I'm able to google is 2012 vintage, so, I'm guessing not nec...

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