I don't think anyone addressed the earlier concerns which you've basically repeated above and it's likely you don't fully understand the entire process.
Quote Originally Posted by TomasL View Post
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Furthermore, I guess that I need to have the lower right corner pressed untill the firmware is transfered, or?
Yes, although you can safely release the screen when you see "Software Loading" on it, it's best to just hold it until Update.exe gives the "Success" message.

I guess that I start GarminCura (have to doewnload it first though, with the selected firmwar, then use updater to transfer the image.
Or, has I got all completely wrong?
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....... does updater lock it into preboot mde, when its connected?
Once Updater.exe starts a flash, an otherwise healthy soft-bricked device will indeed stay in preboot on receiving an initial data package. The biggest problem is the very short time that modern Garmin devices stay in preboot prior to a flash commencing so you must be very fast to press "OK" button on Updater's GUI immediately you see the device details appear in the window next to "USB Device". Boot-looping devices add an extra layer of difficulty because you must also get the timing right before it re-starts or you'll need to start all over again by re-initiating preboot. However you did it with G7ToWin so you can work with Updater.exe too.
Read the initial posts in the threads i linked before, again, and several times if required, until you understand the cure process and why it's necessary. I'm assuming by 'transfer the image' you mean 'flash the RGN firmware file'. The following may help you somewhat:
In brief, Cure fw RGN is only loaded to re-enable Mass Storage Mode by stalling the boot process. The fw must be loaded in preboot mode which is reached by holding the screen as you already did to utilize G7ToWin and confirm its HWID. Once you have MSM again you can make a full backup of the current onboard folders and files (including the important folder [Only registered and activated users can see links. ]) and then either delete everything and copy over a recent 'known-good' backup if you have one, or progressively remove likely corrupt files, or as an absolute last resort reformat FAT32 with [Only registered and activated users can see links. ]. It's then necessary to load original fw, also as an RGN in preboot because the device needs to be able to get well into the boot process to use an onboard GCD fw file (which it can't do with cure fw loaded). That info may make it easier for you to get your head around what to do and why when you re-read the threads.

If you have to post again, say exactly and in detail what you've done and what were the results and any message content from Updater.exe etc..