I did one more attempt and found a link that I converted to zip with "https://github.com/Hagb/decryptBooxUpdateUpx" and installed with: adb sideload update.zip
It worked and past verification.
http://data.onyx-international.cn/ap...t%22:%22%22%7D
Onyx/GoColor7/GoColor7:11/2025-08-28_00-23_4.1-rel_0827_fc8adf71a/8336:user/release-keys"
"md5":"8816086e219f21b39d3959ee250ec152"
"http://firmware-us.boox.com/8816086e219f21b39d3959ee250ec152/update.upx"
And the E-Book Reader booted
