[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 - skyblaster (skyblaster)

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An earlier reference (https://dev.openwrt.org/ticket/17316) uses the following patch:
-wndr4300_mtdlayout=mtdparts=ar934x-nfc:256k(u-boot)ro,256k(u-boot-env)ro,256k(caldata),512k(pot),2048k(language),512k(config),3072k(traffic_meter),2048k(kernel),23552k(ubi),25600k at 0x6c0000(firmware),256k(caldata_backup),-(reserved)
+wndr4300_mtdlayout=mtdparts=ar934x-nfc:256k(u-boot)ro,256k(u-boot-env)ro,256k(caldata),512k(pot),2048k(language),512k(config),3072k(traffic_meter),2048k(kernel),121856k(ubi),123904k at 0x6c0000(firmware),256k(caldata_backup),-(reserved)

I've been using this patch for quite some time without issue as well. The ubi size is slightly different than what @Simpy posted above so I'm wondering how these values are calculated and can they be validated?

It would certainly be convenient to have additional menuconfig/imagebuilder profile entries for those who don't ever care to return to stock. In this case it could be WNDR4300_EXPERIMENTAL
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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#comment2442