Can company change BSD license into any paid? I'm going to use some products shared under free of use licenses (mostly BSD). For example i want to use "on-permise" version of Sentry (https://docs.getsentry.com/on-premise/license/#sentry-license). Sentry offers also paid cloud service. My question is: can any company change their project license in the future? I'm afraid that i will build my projects in depending of free products and some day developers will say: "We're changing license, now you must pay for commercial license or use our paid cloud service".
If you received a copy of a copyrighted work under a particular license in the past, that work is licensed to you under the terms of that license. If the copyright holder stops offering the work under BSD terms, that does not lessen the fact that you already did receive the work under BSD terms. The copyright holder may choose to stop distributing new copies to other people under the old license, but the old license grant offered to you in the past will persist, unless either the license expires, or the licencor explicitly revokes your license grant. The BSD license (and any OSI-approved license) does not have an expiration date, so we do not need to worry about the first possibility. A license can be revoked only if either the terms of the license explicitly allow the licencor to do so, or the license was granted in such a way that the licencor received no economic consideration for the license grant. The BSD license is silent on revocability, so we must see whether there is economic consideration involved. According to Jacobsen v. Katzer, a public open-source license grant may have economic consideration, even absent any exchange of money: Traditionally, copyright owners sold their copyrighted material in exchange for money. The lack of money changing hands in open source licensing should not be presumed to mean that there is no economic consideration, however. There are substantial benefits, including economic benefits, to the creation and distribution of copyrighted works under public licenses that range far beyond traditional license royalties. For example, program creators may generate market share for their programs by providing certain components free of charge. Similarly, a programmer or company may increase its national or international reputation by incubating open source projects. Improvement to a product can come rapidly and free of charge from an expert not even known to the copyright holder. (See also Are licenses irrevocable by default? on OpenSource.SE.) Thus, there is a strong possibility that there is consideration involved in your case, and the licencor may not be able to revoke the license already granted to you.
You can read it, you can examine it to the point where you understand it, and then you can get inspired by the code and write your own code, without copying the code on the website, which does the same thing. If there is no license, then you can do what copyright law allows you to do. You are not allowed to copy the code, or create derived works by taking the code and modifying it.
Generally not. There is a notion in copyright law called the first-sale doctrine in which after a particular copy of a copyrighted work is legitimately sold, the purchaser can sell, lend, lease, give away, or otherwise dispose of the copy as he sees fit. Copyright does not give the copyright holder exclusive rights to authorize resales. See 17 U.S.C. § 109 for the relevant US law; in other countries the same principle is sometimes called exhaustion of rights. There are limits to the doctrine. In the US, it does not allow for for-profit software rental (for most software) or musical record rentals. Moreover, software companies noticed the part where the doctrine applies to a transfer of title (i.e. an actual sale). If you read a typical software EULA, it is generally quite explicit that the software was licensed to you instead of sold; this is why. Courts in the US have often enforced these provisions (particularly if the license imposes limits like "you can't resell it"); European courts have, as far as I know, been far less willing to accept that argument. However, as a general rule resale is specifically not forbidden by copyright.
The agreement linked in the question seems to be or to purport to be, for a non-final, non-production version of the board. I have seen such agreements used, both for hardware and software, used when beta-test versions of products are being distributed to those who agree to do such testing, often in exchange for a reduced price on the final product, or an early look. I have also seen similar language used when an evaluation version of a product is provided free, or at a much reduced price. In such a use, it would be a reasonable contract, it seem to me, and I see no reason why if it were agreed to by both parties in such a situation, it would not be binding. Often such agreements also include a non-disclosure aspect, but this one does not seem to do so. I cannot see how such an agreement could be made applicable automatically, without both parties having chosen to agree to it, and indicated this by signing, clicking, or in some other positive way. I doubt that it could be made automatically applicable, on an "by using this product you agree" basis. I don't know of any physical consumer product, or appliance, sold with such an agreement in ordinary commerce. I am not sure what would happen if a manufacturer wanted to require all purchasers to sign such an agreement. I don't know if it would be binding. I would think that the purchaser's rights under the First Sale doctrice, could be modified by a valid contract agreed to by the purchaser. I do not think that they could simply be revoked by a contract of adhesion, which the purchaser had no choice to decline before making the purchase. As the OP says this was not signed or agreed to in any way, I can't see how it binds the OP.
Both BSD and MIT require you to share "the notice" even when only distributing the software in binary form. For BSD: "Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.". For MIT: "The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.". What you need to do is to include these licenses in a "LEGAL"/"LICENSES" folder of the download package.
Yep, you are. You still need to keep the LICENSE and NOTICE files in the repository, if there were any in your copy of the project. These files contain the terms and conditions for the project, and provide attribution to the original developers. If you're trying to attribute in the UI of your application, you probably should. It's considered courteous and in the spirit of open source as well. This is also related: Do I need to include the full text of the MIT license in the UI of my app?
I'm assuming that you are not seeking to change the license, and so it will remain GPLv3. As long as you've built on the original software, that license still applies. You also need to keep the previous copyright notices, including the names of the original people. Assuming that, everything you're doing is legal, which is what's on topic here. There is some etiquette around forks (which is what you're doing), which would be on topic at the Open Source Stack Exchange. I'm puzzled by your desire to have a different license text. You can't change the license from GPLv3, so that has to stay the same. (If the original has GPLv3 "or, at your option, any later version", you can drop the any other version text if you like.)
You can replace the software on the device The supplier does not have to help you to do so You are correct that because you own the device, you can do what you like with it. That means you can install whatever firmware or other software on it that you like. However, the supplier does not have to provide this to you or assist you in any other way.