Hack The Planet! ... Gemini PDA

[41CH3M157]

DJO,

I think that is a really valid point. I can't help but feel we collectively keep being impatient and wanting progress for the sake of progress, issue is we also are not collectively keeping up with the changes.

Just don't see why we seem to struggle to keep our data organised? Why are we working on so many different projects as humanity in tandem? Seems to me computers are all based around mathematics as much as we work in a way that seem linguistic, underneath it is all mathematics. With mathematics there is only usually one right way to do a specific task in the most efficient way. So why is there so many different high level languages? Why is there so many different types of processor architectures? Surely open sourcing makes the most sense in these scenarios just like any other science.

I am not against progress but how about we all just slow down a bit. Less haste and more speed?

How about working to help humanity to catch up educationally to technology before going down new avenues?

[41CH3M157]

Well  I seem to have relatively exhausted my capacity to look into this area for now. I am glad I have found these documents as they will hopefully be something I will come back to and find useful in future. Now to explore the next avenue, software.

Just going to ask here as you both seem to have some knowledge regarding software development.

I notice that the Android Kernal and Boot Loader have been open sourced. I thought an interesting project for me to have a little go at might be having a look through the Boot Loader source.

https://github.com/dguidipc

Could either of you point me in the right direction of which part is the Boot Loader source?

Thanks in advance,

41CH3M157

[Daniel W]

Hi and welcome to OESF. To really get under the hood of modern computers, including those we call phones, one needs to be or become something of a modern alchemist, able to gather and convert scattered, often incomplete, information into deep, esoteric, knowledge. Then again, while computers are more complex than ever, there's also more information, more powerful tools and better means of communication than ever. I wish you great success.

Just reading the labels, it seems the LK (Linux Kernel, I presume) bootloader for Android 8 is in
https://github.com/dguidipc/gemini-lk-android8
Then there seems to be more stuff in
https://github.com/dguidipc/gemini-lk

While I am a software developer by trade, Android and ARM stuff is largely beyond my current (mostly Windows) horizon, so those are the only pointers I can provide, I'm afraid.

As a comment, yes, previously when trying to find out what I might miss when I got an X25 chip in my early production Gemini, I also came to the conclusion that all X2- chips (as far as I know X20, 23, 25 and 27) are identical, except for their peak clock speed, and the differences are tiny. Documentation for either of the chips, should be equally valid, though references to configuration, software and standards might be out of date in older documents.

[41CH3M157]

Hi Daniel,

Thanks for your post and encouragement, a really nice read, it gives me hope. I am pleased to see we seem to have a common interest in esoteric knowledge. All is data; input, storage, process, output. I agree that there is more information out there than ever and it will take quite a few modern day alchemists to organise it all so it can fit on one stone, tablet.

I really appreciate you sharing you knowledge with me. I have done a little research since I first read your post and it seems a very good place to start. I am still unsure if it is the primary or secondary boot loader, though I am sure I will find out in time. Regards the chip sets being similar enough to make some comparisons I am very happy to hear that.

Found an interesting video today on the boot loading process of ARM chips. Likely simple for someone like yourself, though I found it enlightening regarding how to read tech docs and the boot process of ARM chips, perhaps it may assist others.

Again many thanks for you input and encouragement, I appreciate it more than you likely realise.

Yours Faithfully,

41CH3M157

[41CH3M157]

Here is a video I found on ARMs ROM boot loading process. Was helpful to understanding a bit more about the above, and also how to go about reading technical documents.

https://youtu.be/DV5S_ZSdK0s

[41CH3M157]

Hi All,

After researching Little Kernal, and other options for SPLs (Secondary Program Loaders)/ MLOs (Memory Loaders), I wonder why Android doesn't use U-Boot instead of Little Kernal. U-Boot's documentation seems much better. Perhaps there's a valid reason?

Tomorrow I hope to make concise the information from the prior video to make it easier for me to revise the information. Then do some digging around in U-Boot's GIT (https://github.com/u-boot/u-boot/blob/master/README) to get a better idea of how it  works. Thanks again to everyone who has posted, I am really pleased to have found such a welcoming community.

Yours Faithfully,

41CH3M157

p.s. Still love my Gemini, do everything on it, getting faster at typing, keeps me super motivated.

[Eric BF]

Slightly off-topic but have you considered the Pyra? It's a community driven PDA, fully open (as can be these days: does not include some of the radio component drivers). Not out yet but soon (hopefully).

[41CH3M157]

Hi Eric,

I hadn't seen it before so thanks for the share. At the same time, to me; and it is just personal preference, it is just not in a form factor that I would find as appealing. The keyboard in the Gemini is just so good. With every piece of hardware I have felt I had to make some kind of compromise, I don't feel this way about the Gemini. Additionally, the more I look at the Gemini, the more I realise that most ARM devices are relatively open for those with the time and patience to do the research, those with the eyes to see as they say. Personally, at least for now, I think I am more interested in working on learning the parts of the Gemini that are open, and eventually I will attempt to backwards engineer any parts that I find are not.

Yours Faithfully,

41CH3M157

[41CH3M157]

Summarised Information Gathered from Video Above

Arm chips have three levels of boot loader.[/u]

1) ARM ROM boot loader; etched into chip.

2) SPL (Secondary Program Loader)/ MLO (Memory Loader);
AKA 'Primary Boot Loader' though ROM is first, a bit confusing, usually stored on internal SD.

3) Secondary Boot Loader;
Similarly to above, a bit confusing as it is actually third; again usually stored on internal SD.

Process of Booting

ARM ROM runs automatically when chip powered.
 
ROM searches peripherals, in serial, searching for SPL/MLO.

(I read that there is a private key in ROM, the MLO must have the public key to be trusted.
Though I will need to do some more research into this to know for sure.)

MLO loaded onto chips internal RAM, usually small; around 64kb; the ROM hands off.

MLO has firmware to load PCB RAM, loads secondary boot loader into PCB RAM;
and a config folder which I also need to do some more research on.

Once secondary boot loader on PCB RAM the MLO hands off.

Secondary Boot Loader then searches peripherals for the Kernal Boot Loader.

Further Research Since

Seems the main two SPL/MLOs are 'Tiny Kernal' for Android and 'U-Boot' for everything else.

Quite pleased most of the important stuff can be played with as it's open source; may need the public key if needed. Though the ROM is hard etched, it seems relatively standardised, so there should be info on how it works and how one can interact with it.

It seems the chips being setup as they are in the Gemini (clustered multi core) there will be a chip that acts as master in the boot process (perhaps the MCU?), and something called a... spin table? to boot the rest of the cores. Will have to more research, but so far so good.

Hope this helps someone. It helps me organise myself, so thanks for putting up with my blabbering. I may get things wrong, I know little about all this, just sharing what I learn as I go along. If you notice something I have misunderstood please feel free to let me know. Next I'll look for ARM Assembly and more about U-Boot and Little Kernal.

Yours Faithfully,

41CH3M157