[Nothing Phone 1] the_raz:
1. Yes, since all this process both flashing and critical flashing has been unlocked. Idk if it matters, edl flash doesn't re-lock them as I read somewhere, might be unimportant though.

2. Yes I can access recovery mode directly from the bootloader on partition b on the phone. I set a to be the active slot and did fastboot -w with following message

edit: managed to get the same on b

C:\Windows\system32>fastboot --set-active=a

Setting current slot to 'a' OKAY [ 0.000s]

Finished. Total time: 0.016s

C:\Windows\system32>fastboot -w

Erasing 'userdata' OKAY [ 0.031s]

F2FS-tools: mkfs.f2fs Ver: 1.16.0 (2023-04-11)

Info: Disable heap-based policy

Info: Debug level = 1

Info: Trim is disabled

Info: Set conf for android

Info: Enable Project quota

Info: Segments per section = 1

Info: Sections per zone = 1

Info: sector size = 512

Info: total sectors = 474394264 (231637 MB)

Info: zone aligned segment0 blkaddr: 512

Info: add quota type = 0 => 4

Info: add quota type = 1 => 5

Info: add quota type = 2 => 6

Info: format version with

""

[f2fs_init_sit_area: 640] Filling sit area at offset 0x00600000

[f2fs_init_nat_area: 674] Filling nat area at offset 0x01a00000

[f2fs_write_root_inode:1292] Writing root inode (hot node), 2ba00 0 200 at offset 0x00178688

[f2fs_write_default_quota:1368] Writing quota data, at offset 0002c001, 0002c002

[f2fs_write_qf_inode:1425] Writing quota inode (hot node), 2ba00 0 200 at offset 0x00178689

[f2fs_write_default_quota:1368] Writing quota data, at offset 0002c003, 0002c004

[f2fs_write_qf_inode:1425] Writing quota inode (hot node), 2ba00 0 200 at offset 0x00178690

[f2fs_write_default_quota:1368] Writing quota data, at offset 0002c005, 0002c006

[f2fs_write_qf_inode:1425] Writing quota inode (hot node), 2ba00 0 200 at offset 0x00178691

[f2fs_update_nat_root:1479] Writing nat root, at offset 0x00001a00

[f2fs_add_default_dentry_root:1676] Writing default dentry root, at offset 0x0002c000

Info: Overprovision ratio = 0.300%

Info: Overprovision segments = 347 (GC reserved = 340)

[f2fs_write_check_point_pack: 837] Writing main segments, cp at offset 0x00000200

[f2fs_write_check_point_pack: 993] Writing Segment summary for HOT/WARM/COLD_DATA, at offset 0x00000201

[f2fs_write_check_point_pack:1020] Writing Segment summary for HOT_NODE, at offset 0x00000202

[f2fs_write_check_point_pack:1032] Writing Segment summary for WARM_NODE, at offset 0x00000203

[f2fs_write_check_point_pack:1043] Writing Segment summary for COLD_NODE, at offset 0x00000204

[f2fs_write_check_point_pack:1051] Writing cp page2, at offset 0x00000205

[f2fs_write_check_point_pack:1071] Writing NAT bits pages, at offset 0x000003fe

[f2fs_write_check_point_pack:1092] Writing cp page 1 of checkpoint pack 2, at offset 0x00000400

[f2fs_write_check_point_pack:1111] Writing cp page 2 of checkpoint pack 2, at offset 0x00000405

[f2fs_write_super_block:1144] Writing super block, at offset 0x00000000

Info: format successful

terminating with uncaught exception of type std::eek:ut_of_range: basic_string

and then rebooted, it tried booting once and it went to a screen "Can't load Android system. Data might be corrupt. bla bla" with an option to factory reset or try again. I hit factory reset and it bootloops and tries to boot a couple of times but then lands me in the bootloader, can't enter recovery or fastbootd on slot a so I guess I'm going to work with slot b.

"did you erase everything" do you mean simply using the factory reset option in recovery mode? If so then yes I did.

I'm going to test your method of manually flashing both partitions and stopping it before it boots etc. According to my recovery logs though I'm ro.build.version.incremental=1669043167 i.e. 1.1.7. global so I'm not sure if I have to flash incrementally, like 1.1.7 -> 1.1.7 hotfix -> 1.1.8 or go directly to 1.5.2 but I guess I'll find out hehe.. Going to flash in fasdtbootd also, hope thats correct or if you have to flash some in fastboot. Well the night is young so I'm about to find out.

by flash fastboot ROM you mean flash a ROM using fastboot(-/d) or actually mean flash like a fastboot.img? Sorry I'm quite the noob and just want to make sure I'm understanding.