Vent: I am on the verge of smashing this phone apart.

[technix]

TL;DR: Do not touch any non-mainstream consumer devices without service manual or hacking community available, if you are not within their intended user range.

My ISP recently introduced unlimited data plans, but it is only available as new subscriptions. When I asked my ISP about this plan they gave me the information that since I am already a 5-year subscriber I can get a 150-dollar phone for free with a 2-year contract of keeping my subscription alive (no obligation of using my SIM card in the phone - just keep using my SIM card and I get an additional phone) So I can get a new subscription with this unlimited data plan, and use my old subscription entitlement to get a phone solely used for an access point. The 150-dollar phone in question is this Oppo A37m. I have my hardened iPhone. I won't use this as my daily driver.

Then as per "required by their sales rules," a few software is loaded into the phone (activated using the salesperson's SIM card.) I have no trust in that software. Now either I have to wipe the entire machine clean, or this is a pile of trash for me and I cannot throw it away. Resetting the phone using built-in recovery mode does not wipe all pre-loaded software. It is nigh difficult to hunt down a custom ROM for the device. It have no known bootloader unlocking mechanism. And I cannot put it into early bootloader mode to even try hacking it.

I am on the verge of unleashing my dremel on it.

[Rick Law]

Since with your name is "From Shanghai ..."

I assume this phone and purchase were in China?  Is it common there the phone company would load stuff on your phone this way?

If it was me getting the phone, that alone would make me walk out.  I don't like the idea of the Sale Clerk just adding stuff onto my phone like that at all.

[technix]

Since with your name is "From Shanghai ..."

I assume this phone and purchase were in China?  Is it common there the phone company would load stuff on your phone this way?

Yes it is in China. And yes if you purchase a phone from ISP, especially if under a contract (like mine - I did not really pay any money but this happens regardless whether I paid or not) you are more likely than not have a few software forced on you.

The ISP does this in the name of a "starter kit" (as the apps are a few commonly used apps in China, along with a few of ISP's own apps, but all installed from unknown sources of ISP) that seemed to work well with the general public as the phone is ready to use (including putting in social network credentials.) But since I am trained in computer science this cringes the hell out of me.

If it was me getting the phone, that alone would make me walk out.  I don't like the idea of the Sale Clerk just adding stuff onto my phone like that at all.

When family member is involved it gets complicated. When it is an extremely domineering mother it gets EXTREMELY complicated.

[Cyberdragon]

Have you tried rooting it? Might cause a bit of trouble at first, but if you can get the sofware off you can remove the root access afterwards.

[RGB255_0_0]

Have you tried rooting it? Might cause a bit of trouble at first, but if you can get the sofware off you can remove the root access afterwards.

Locked bootloader. Can't flash TWRP or custom kernel. Only option is if there is a software exploit to get a temporary root. Didn't find anything that anyone made public.

Since it's not a popular device there are too few looking. Maybe get information on the MediaTek chipset and see if you can compile a kernel as the source should be public per licensing.

But is it with all that hassle? Sell the device and buy something useful.

[technix]

Have you tried rooting it? Might cause a bit of trouble at first, but if you can get the sofware off you can remove the root access afterwards.

Locked bootloader. Can't flash TWRP or custom kernel. Only option is if there is a software exploit to get a temporary root. Didn't find anything that anyone made public.

Since it's not a popular device there are too few looking. Maybe get information on the MediaTek chipset and see if you can compile a kernel as the source should be public per licensing.

But is it with all that hassle? Sell the device and buy something useful.

I have doubts whether I can legally sell the device without breaching the contract.

Should I be able to sell the device I will sell it and grab myself a SIM7600CE module instead, stick it to a Raspberry Pi 3 and create a mobile access point that way.