Is it possible to upgrade a GSI ROM without having to wipe data?

[ArkBlitz]

I've been using the G6 Play for about a week now, and first thing I did was to flash a custom ROM. It was complicated, but in the end I managed to do it. However, I'm having problems with the current ROM I'm using, Resurrection Remix (namely the lack of FM Radio, and the fact that it randomly reboots to recovery while I'm using Twitter specifically), so I was trying to upgrade my phone to what seems to be the next release of RR. However, I can't afford to lose my current data because I don't have enough storage space to run Titanium Backup, and most non-GSI ROMs that I know of can be upgraded without requiring the full wipe of data. What I've already tried is the following:

• Delete the current System partition but NOT Data
• Use Fastboot to flash the new ROM
• Return to TWRP to fix the partition, then resize it
• Reinstall OpenGApps
• Reinstall the verity disabler (Disable_Dm-Verity_ForceEncrypt_08.18.2019)
• Install Busybox
• Install Magisk
• Install Magisk-Props to avoid the "Google Play uncertified" error
• Clear Dalvik and cache
• Reboot

However, every time I do this with anything but the ROM I'm currently running, the system attempts to boot and after the boot logo appears for a few minutes, it reboots directly to TWRP. (Same thing happens to me at random while using the Twitter app specifically, for some reason!). My question is: is it absolutely necessary to wipe data in order to upgrade a GSI ROM from a version to the next? If so, what is the fastest way to restore all data, and should I invest on an external SD card?

 

[ry755]

I think it mostly depends on the rom you're using, some of them seem to be more sensitive than others. I know in the past I've been able to upgrade AOSP and Descendant successfully.