Hello
Let's say I have this scenario
-Firmware is in plainText
-No Flash Encryption Enabled
-No keys , efuses burned .. chip is brand new
Now .. I
-Generate a Flash Encryption Key
-Burn it to efuse
-didn't burn any efuses manually (no encrypt_cnt , cnf ..etc )
-Now I open menuconfig , enable flash encryption in Release mode
-Flash the the image normally as plainText .
will this burn the remaining efuses automatically to match the Release mode ?
Note:
I ask this because previously I had a chip that was in dev mode , then I disabled FE and then re enabled it in release mode
that didn't burn any efuses and I got an error (warning) .. device is not secure . difference between dev and release mode in efuses
Thanks
Flash Encryption & Pre Generated Key , must manually burn efuses ?
Re: Flash Encryption & Pre Generated Key , must manually burn efuses ?
Yes, that's the best way to do this.plusorc wrote: ↑Wed Jan 29, 2020 1:02 amLet's say I have this scenario
-Firmware is in plainText
-No Flash Encryption Enabled
-No keys , efuses burned .. chip is brand new
Now .. I
-Generate a Flash Encryption Key
-Burn it to efuse
-didn't burn any efuses manually (no encrypt_cnt , cnf ..etc )
-Now I open menuconfig , enable flash encryption in Release mode
-Flash the the image normally as plainText .
will this burn the remaining efuses automatically to match the Release mode ?
There is no workflow at the moment for taking the same device from Development mode to Release mode. If you flash a release mode firmware on a chip which already using Development mode flash encryption then you get this warning, and it stays in Development mode.plusorc wrote: ↑Wed Jan 29, 2020 1:02 amNote:
I ask this because previously I had a chip that was in dev mode , then I disabled FE and then re enabled it in release mode
that didn't burn any efuses and I got an error (warning) .. device is not secure . difference between dev and release mode in efuses
We made the decision not to support this workflow because it's easier to discourage taking a device from Development to Release mode than to try to think of every possible sequence of updates that might leave the device in an insecure state. If you have a use case for using the same chip in first Development then Release mode then let us know, we might be able to figure something out.
Re: Flash Encryption & Pre Generated Key , must manually burn efuses ?
Thank you so muchYes, that's the best way to do this.
I actually don't , I just assumed that the chip will match the sdkconfig settings with the efuse (0 to 1 only of course)There is no workflow at the moment for taking the same device from Development mode to Release mode
If you have a use case for using the same chip in first Development then Release mode then let us know
As far as I understand , Even if the chip is in FE Dev mode , and I burn the remaining efuse bits (dl_enc,dl_dec,cnf,cnt, jtag,console_debug) , it will eventually become a Release mode .
Thanks again for the great help .
Re: Flash Encryption & Pre Generated Key , must manually burn efuses ?
That's correct. The reason we don't officially document this process is that it's fiddly and easy to do it incorrectly, so we recommend using a new whole new chip for Release mode encryption.
Angus
Re: Flash Encryption & Pre Generated Key , must manually burn efuses ?
You're a great help
Thank You
Thank You
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