[FS#146] wndr 3700v4 and 4300v1 couldn't effectively use 128 nand flash space

[LEDE Bugs]

The following task has a new comment added:

FS#146 - wndr 3700v4 and 4300v1 couldn't effectively use 128 nand flash space
User who did this - Mauro Mozzarelli (ezplanet)

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Would it be possible to create a separate alternative configuration for WNDR3700v4 that changes flash mapping? In the  section there can be a warning and instruction to copy caldata_backup the first time the new firmware is flashed.

This would save those like me who already use the new flash map having to apply the patch to every git update.
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More information can be found at the following URL:
https://bugs.lede-project.org/index.php?do=details&task_id=146#comment1447