Safely Edit Emmc ProdInfo?

[autumns]

So I’m pretty inexperienced here and want to make sure with any experts on here that what I’m doing won’t cause any permanent damage, here it goes.

I want to change the Wifi Region Code on an OLED Mariko Switch, specifically just for the emunand. Mine is currently using a Japanese motherboard which through software limitations is not able to fully utilize 5Ghz connections. The only official way I can find to region change this is through a setting in Incognito on Tinfoil, but Incognito is not available on Mariko Switches. According to switchbrew. org/w/index.php?title=Calibration&mobileaction=toggle_view_desktop the offset in the prodinfo to change the WlanCountryCodes is 0x0088, which seems to be what controls this value. By comparing my OLED Nand dump to sthetix’ decrypted donor OLED nand dump I found that this value seems to be 32 for US region vs 31 for JP. I dumped my nand, decrypted the prodinfo using my console keys in NxNandManager, edited it in HxD, saved and reencrypted it, then took my original Nand dump and replaced the prodinfo in it with the reencrypted edited file. Then I plan to create a fresh partition on an sd using this modified nand dump with nxnandmanager, and according to this guide for a similar process, forum.devchroma. nl/index.php/topic,222.msg652.html#msg652 , I insert the SD in the console, boot up and factory reset from system settings. Then, when it restarts, the changes should have applied and the emunand will function normally with US wifi capabilities.

Does this seem feasible? Assuming I keep a clean backup of the Nand, Is there a risk that I’ll actually brick my switch by doing this? Is any of this incorrect? And Is there an easier, noob friendly way to do this?

 

[petspeed]

I don't know whether what you are doing will work (changing wifi region) but as long as you have a backup, either full sysmmc or just of prodinfo, then you can always restore if something goes wrong. So there should be no brick risk.
However you could create an emummc from you sysmmc with hekate and test on that first. Then you don't risk anything

 

[Hayato213]

You can get a dual 5 GHz router.

 

[autumns]

You can get a dual 5 GHz router.

my router is dual 5 Ghz, i was inspired to do this when i had to stay in an airbnb for a few days that was only 5Ghz wifi and my switch couldn’t detect it

I don't know whether what you are doing will work (changing wifi region) but as long as you have a backup, either full sysmmc or just of prodinfo, then you can always restore if something goes wrong. So there should be no brick risk.
However you could create an emummc from you sysmmc with hekate and test on that first. Then you don't risk anything

Thank you this is what I was most worried about, I will try it and if it doesn’t work i’ll just restore the old one

Also for the second point i am using my emummc with a full backup of the current emummc data on my computer so it should be safe. Which I think is what you’re saying. Even though I would prefer to fix it on both emu and sysnand, I don’t want to edit the sysnand just because of ban risk with mismatched hardware info with serial number vs wifi region as I would like to be able to go online on there. Thanks so much for the help!