I can confirm that OFW 4.88 works with 1.500 TiB (1,536 GiB, ~1.65TB) = 3,221,225,472 sectors with 512 bytes, but it is not
safe ("Restore File System" issue).
For a
safe working system use 963 GiB = 1,034,013,376,512 Bytes = 2,019,557,376 sectors with 512 bytes (*1).
Please note those different units. The actual limit is 1.5 TiB (recognize the i, powers of 1024), but harddisk manufacturer's always use TB (without i, powers of 1000) and this is nearly ~1.65TB. The PS3 OFW uses GiB under system information, but writes it as "GB"

So no new limit found, just confirming the already known one for OFW 4.88 with already known "Restore File System" issue.
PS3: Fat CECHH04
Tested HDD: Samsung/Seagate Spinpoint ST2000KM003 (2TB)
Tested SSD: Samsung 870 Evo (2TB)
Software:
Ultimate Boot CD (v5.3.9, with
HDAT2 v5.3 under HDD > Diagnostics), optionally use Linux's "hdparm -N p<sectors> --yes-i-know-what-i-am-doing /dev/<drive>"
- Make a backup of the PS3 system with the old HDD/SSD (settings, games, saved data)
- Burn Ultimate Boot CD to a DVD (ISO is bigger than 700 MB)
- Prepare PC: open case to (later) connect HDD, enable CSM mode (non-UEFI)
- Boot PC from Ultimate Boot CD
- Choose HDD > Diagnostics > HDAT2
- After HDAT2 loaded connect the HDD to the PC
- Press D to re-detect all drives
- Select the correct HDD/SSD
- Choose to set the protected area (SATA feature HPA)
- If it is not present, maybe you can unfreeze it. (Thanks Berion)
- On the field new user value press the INS key to enter the wanted available sectors: 3,221,225,472 (without thousands separators)
- Then set the new value with the S key
- Put the prepared HDD/SSD into the PS3 and initialize it with OFW 4.88 from an USB stick as usual
- Additionally test "Restore File System" from the PS3 safe mode (will reset your video/audio settings). (Thanks sandungas)
- Safe mode (since OFW 2.50)
- Sony's "Using PS3 Safe Mode" video
- PS3 in standby mode = LED red (XMB: "Turn Off system" -or- hold power button until turrned off); hold power button for ~13s and release it when the LED turns red again; again hold power button for ~10s and release it after the 3rd beep (double beep)
- Connect a controller via USB cable to the PS3
- Execute "Restore File System"
- Check that it does not want to format the drive and that the PS3 system works afterwards
- Restore backup to the PS3 system with the new HDD/SSD
While checking my available drives for the SATA feature HPA I recognized that all my HDDs (6) supported it out-of-the-box, but not all of my SSDs:
- SANDisk Ultra 3D (500GB, 4TB): supports HPA
- Adata SU650 (1.9TB): does not support HPA out-of-the-box, maybe have to unfreeze as Berion explained below?!? (no able to re-check)
- Samsung 870 Evo (2TB): supports HPA
During my searches I also found the following note about HPA and Linux:
https://www.thomas-krenn.com/en/wik...ting_HPA_Disabling_for_Affected_Linux_Systems
*1 = Did some tests to narrow down the actual "Restore File System" issue:
- 500GB HDD without HPA: works / 9,767,73,168 sectors = 500,107,862,016 bytes = ~465.8 GiB
- 500GB HDD with HPA down to 400GiB: works, 400 GiB = 429,496,729,600 bytes = 838,860,800 sectors (of 512 [/4096])
- 2TB SSD with HPA down to 400GiB: works
- Conclusion: Software issue in OFW with "Restore File System" functionality.
- Finding limit <1.5 TiB for "Restore File System" functionality:
- 1.00 TiB: FAILS, 1,048,576 MiB = 1,099,511,627,776 Bytes = 2,147,483,648 sectors (of 512)
- 1.00 TiB - 1 sector: FAILS, 2,147,483,647 sectors (32bit integer limit)
- 1,000 GiB: FAILS, 1,024,000 MiB = 1,073,741,824,000 Bytes = 2,097,152,000 sectors (of 512)
- 800 GiB: works, 819,200 MiB = 858,993,459,200 Bytes = 1,677,721,600 sectors (of 512)
- 900 GiB: works, 921,600 MiB = 966,367,641,600 Bytes = 1,887,436,800 sectors (of 512)
- 950 GiB: works, 972,800 MiB = 1,020,054,732,800 Bytes = 1,992,294,400 sectors (of 512)
- 975 GiB: FAILS, 998,400 MiB = 1,046,898,278,400 Bytes = 2,044,723,200 sectors (of 512)
- 960 GiB: works, 983,040 MiB = 1,030,792,151,040 Bytes = 2,013,265,920 sectors (of 512)
- 970 GiB: FAILS, 993,280 MiB = 1,041,529,569,280 Bytes = 2,034,237,440 sectors (of 512)
- 965 GiB: FAILS, 988,160 MiB = 1,036,160,860,160 Bytes = 2,023,751,680 sectors (of 512)
- 962.75 GiB: works, 985,856 MiB = 1,033,744,941,056 Bytes = 2,019,033,088 sectors (of 512)
- 963.00 GiB: works, 986,112 MiB = 1,034,013,376,512 Bytes = 2,019,557,376 sectors (of 512)
- 963.50 GiB: FAILS, 986,624 MiB = 1,034,550,247,424 Bytes = 2,020,605,952 sectors (of 512)
- 963.25 GiB: FAILS, 986,368 MiB = 1,034,281,811,968 Bytes = 2,020,081,664 sectors (of 512)